View source for Interstate 5 in Washington

{{short description|Interstate highway in Washington}}
{{Use American English|date=May 2025}}
{{redirect-synonym|WA 5|{{ushr|Washington|5}}}}
{{good article}}
{{Use mdy dates|date=June 2018}}
{{highway detail hatnote|Interstate 5}}
{{Infobox road
|state=WA
|type=I
|route=5
|alternate_name=Purple Heart Trail
|section=020
|map={{maplink-road|frame-height=250|from=Interstate 5 in Washington.map}}
|map_custom=yes
|map_notes=A map of Western Washington with I-5 highlighted in red
|length_mi=276.62
|length_round=2
|length_ref=<ref name="log">{{WSDOT State Highway Log |year=2013 |pages=220–322 |link=yes |style=alt |access-date=June 14, 2018}}</ref><ref name="FHWA-log">{{cite web |date=December 31, 2017 |title=Table 1: Main Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of December 31, 2017 |url=https://www.fhwa.dot.gov/planning/national_highway_system/interstate_highway_system/routefinder/table01.cfm |publisher=[[Federal Highway Administration]] |access-date=June 15, 2018}}</ref>
|established=August 14, 1957<ref name="AASHO-1957">{{cite map |title=Official Route Numbering for the National System of Interstate and Defense Highways |date=August 14, 1957 |url=https://commons.wikimedia.org/wiki/File:Interstate_Highway_plan_August_14,_1957.jpg |publisher=[[American Association of State Highway Officials]], [[Public Roads Administration]] |access-date=June 14, 2018}}</ref><ref name="FHWA-1996">{{cite journal |last=Weingroff |first=Richard F. |title=Federal-Aid Highway Act of 1956, Creating the Interstate System |url=https://highways.dot.gov/public-roads/summer-1996/federal-aid-highway-act-1956-creating-interstate-system |journal=Public Roads |location=Washington, D.C. |publisher=[[Federal Highway Administration]] |volume=60 |issue=1 |year=1996 |issn=0033-3735 |access-date=June 14, 2018}}</ref>
|history=Completed in 1969<ref name="HL-EM1969">{{cite web |last=Dougherty |first=Phil |date=April 10, 2010 |title=Interstate 5 is completed in Washington state on May 14, 1969. |url=http://www.historylink.org/File/9393 |work=[[HistoryLink]] |access-date=June 14, 2018}}</ref>
|tourist={{plainlist|
*[[File:MUTCD M10-1.svg|20px|alt=|link=]] [[Cascade Loop Scenic Byway]]
*[[Lewis and Clark Trail Scenic Byway]]
*[[Skagit Valley Agricultural Scenic Corridor]]
}}
|direction_a=South
|terminus_a={{jct|state=OR|I|5}} at the [[Oregon]] state line in [[Vancouver, Washington|Vancouver]]
|junction={{plainlist|
*{{jct|state=WA|I|205}} in [[Salmon Creek, Washington|Salmon Creek]]
*{{jct|state=WA|US|12}} near [[Centralia, Washington|Centralia]]
*{{jct|state=WA|US|101}} in [[Tumwater, Washington|Tumwater]]
*{{jct|state=WA|SR|16}} in [[Tacoma, Washington|Tacoma]]
*{{jct|state=WA|I|405|SR|518}} in [[Tukwila, Washington|Tukwila]]
*{{jct|state=WA|I|90}} in [[Seattle]]
*{{jct|state=WA|SR|520}} in Seattle
*{{jct|state=WA|I|405|SR|525}} in [[Lynnwood, Washington|Lynnwood]]
*{{jct|state=WA|US|2}} in [[Everett, Washington|Everett]]
*{{jct|state=WA|SR|20}} in [[Burlington, Washington|Burlington]]
}}
|direction_b=North
|terminus_b={{jct|province=BC|Hwy|99}} at the [[Canada–United States border|Canadian border]] in [[Blaine, Washington|Blaine]]
|counties=[[Clark County, Washington|Clark]], [[Cowlitz County, Washington|Cowlitz]], [[Lewis County, Washington|Lewis]], [[Thurston County, Washington|Thurston]], [[Pierce County, Washington|Pierce]], [[King County, Washington|King]], [[Snohomish County, Washington|Snohomish]], [[Skagit County, Washington|Skagit]], [[Whatcom County, Washington|Whatcom]]
|previous_type=SR
|previous_route=4
|next_type=SR
|next_route=6
}}

'''Interstate 5''' ('''I-5''') is an [[Interstate Highway System|Interstate Highway]] on the [[West Coast of the United States]] that serves as the region's primary north–south route. It spans {{convert|277|mi|km|0}} across the state of [[Washington (state)|Washington]], from the [[Oregon]] state border at [[Vancouver, Washington|Vancouver]], through the [[Puget Sound region]], to the [[Canada–United States border|Canadian border]] at [[Blaine, Washington|Blaine]]. Within the [[Seattle metropolitan area]], the freeway connects the cities of [[Tacoma, Washington|Tacoma]], [[Seattle]], and [[Everett, Washington|Everett]].

I-5 is the only interstate to traverse the whole state from north to south and is Washington's busiest highway, with an average of 274,000 vehicles traveling on it through [[Downtown Seattle]] on a typical day. The segment in Downtown Seattle is also among the widest freeways in the United States, at 13 lanes, and includes a set of [[Local–express lanes|express lanes]] that [[reversible lane|reverse direction]] depending on time of the day. Most of the freeway is four lanes in rural areas and six to eight lanes in suburban areas, including a set of [[high-occupancy vehicle lane]]s in the latter. I-5 also has three related [[List of auxiliary Interstate Highways|auxiliary Interstates]] in the state, [[Interstate 205 (Oregon–Washington)|I-205]], [[Interstate 405 (Washington)|I-405]], and [[Interstate 705|I-705]], as well as several designated [[Business routes of Interstate 5|business routes]] and state routes.

The freeway follows several historic railroads and [[wagon trail]]s developed during American settlement of [[western Washington]] in the mid-to-late 19th century. The [[Washington State Legislature|state legislature]] incorporated local roads into the [[Pacific Highway (United States)|Pacific Highway]] in 1913, connecting the state's southern and northern borders between Vancouver and Blaine. The Pacific Highway was built and paved over the next decade, and became the northernmost segment of the national [[U.S. Route 99]] (US&nbsp;99) in 1926.

The federal government endorsed the creation of a national expressway system in the 1940s, including several [[bypass (road)|bypasses]] on US&nbsp;99 that were built by the state in the early 1950s. The state's planned [[toll road|toll superhighway]] in the Seattle area was shelved in favor of a federally-funded freeway under the new Interstate Highway System, under which I-5 was created in 1957. Construction of I-5 was completed in 1969, and several segments of the highway have been widened or improved in the decades since.

==Route description==

Interstate 5 is the only Interstate to traverse Washington from north to south, serving as the primary highway for the [[Western Washington|western]] portion of the state.<ref>{{cite journal |last=Horton |first=Jeffery L. |date=November 2014 |title=Surviving An Interstate Bridge Collapse |url=https://highways.dot.gov/public-roads/novemberdecember-2014/surviving-interstate-bridge-collapse |journal=Public Roads |volume=78 |issue=3 |publisher=Federal Highway Administration |access-date=June 14, 2018}}</ref> It is listed as part of the [[National Highway System (United States)|National Highway System]] and the state's Highways of Statewide Significance program, recognizing its connection to major communities.<ref>{{cite map |publisher=[[Federal Highway Administration]] |title=National Highway System: Washington |url=https://www.fhwa.dot.gov/planning/national_highway_system/nhs_maps/washington/wa_washington.pdf |date=October 1, 2012 |access-date=June 14, 2018}}</ref><ref>{{cite web |title=Transportation Commission List of Highways of Statewide Significance |url=https://www.wsdot.wa.gov/sites/default/files/2006/03/16/HSSlist2009mod2.pdf |publisher=[[Washington State Transportation Commission]] |date=July 26, 2009 |access-date=June 14, 2018 |archive-url=https://web.archive.org/web/20130724190950/http://www.wsdot.wa.gov/NR/rdonlyres/50EC9EB9-DB3D-4823-B5D2-5348409FB8CE/0/HSSlist2009mod2.pdf |archive-date=July 24, 2013 }}</ref> I-5 has three [[List of auxiliary Interstate Highways|auxiliary Interstate Highways]] within Washington: [[Interstate 205 (Oregon–Washington)|I-205]], an easterly bypass of [[Portland, Oregon]], and [[Vancouver, Washington|Vancouver]]; [[Interstate 405 (Washington)|I-405]], bypassing [[Seattle]] via the [[Eastside (King County, Washington)|Eastside]]; and [[Interstate 705|I-705]], a short spur into [[Tacoma, Washington|Tacoma]].<ref name="WSDOTMap">{{cite map |year=2014 |title=Washington State Highways 2014–2015 |scale=1:842,000 |url=https://www.wsdot.wa.gov/sites/default/files/2006/06/13/TouristMapFront_withoutHillshade.pdf |publisher=Washington State Department of Transportation |postscript=none |access-date=June 14, 2018 |archive-date=February 21, 2017 |archive-url=https://web.archive.org/web/20170221194441/https://www.wsdot.wa.gov/NR/rdonlyres/2D10703F-9ADF-4A95-A14E-2A36FEAF1C20/0/Statewide2014NoHillshade.pdf }}, with [https://www.wsdot.wa.gov/Publications/HighwayMap/view.htm inset maps].</ref><ref>{{cite web |date=December 31, 1997 |title=The Dwight D. Eisenhower System of Interstate and Defense Highways: Part II – Mileage |url=https://www.fhwa.dot.gov/highwayhistory/data/page02.cfm |publisher=Federal Highway Administration |access-date=August 6, 2018}}</ref> It was designated as the [[Purple Heart]] Trail in 2013 by the [[Washington State Transportation Commission]] to honor wounded military veterans.<ref>{{cite news |last=Hill |first=Christian |date=August 2, 2013 |title=I-5 in Washington becomes Purple Heart Trail to honor veterans |url=https://www.columbian.com/news/2013/aug/02/state-honors-vets-with-i-5-name/ |work=[[The Columbian]] |access-date=October 1, 2018}}</ref>

The freeway runs through the most densely populated region of Washington state, with 4.6&nbsp;million people living in the nine counties on the corridor, approximately 70 percent of the state's population.<ref>{{cite news |last=MacDonald |first=Douglas |date=May 15, 2013 |title=Trans-poor-tation 3: No high five for I-5 |url=https://crosscut.com/2013/05/fixing-interstate5-is-washingtons-top-priority |work=[[Crosscut.com]] |access-date=June 21, 2018}}</ref><ref>{{cite news |last=Lewis |first=Mike |date=March 27, 2001 |title=I-5 drives population increase |page=A1 |work=[[Seattle Post-Intelligencer]]}}</ref> Several of the largest cities along the I-5 corridor are also connected by the parallel [[Amtrak Cascades|''Cascades'']], a regional train service between [[Eugene, Oregon]], and [[Vancouver]], British Columbia, operated by [[Amtrak]] and funded by the state governments of Oregon and Washington.<ref>{{cite news |last1=Bacon |first1=John |last2=Farley |first2=Josh |date=December 18, 2017 |title=6 dead after Amtrak Cascades train derails onto Interstate 5 near Tacoma |url=https://www.statesmanjournal.com/story/news/2017/12/18/amtrak-cascades-train-derails-onto-interstate-5-near-olympia-washington/961115001/ |work=[[Statesman-Journal]] |access-date=June 17, 2018}}</ref><ref>{{cite web |title=Passenger Rail in Washington |url=http://www.wsdot.wa.gov/rail |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20180629140542/http://www.wsdot.wa.gov/rail |archive-date=June 29, 2018 |access-date=June 17, 2018}}</ref>

I-5 is maintained by the [[Washington State Department of Transportation]] (WSDOT), who conduct an annual survey of traffic volume that is expressed in terms of [[annual average daily traffic]] (AADT), a measure of traffic volume for any average day of the year. The stretch of I-5 through [[Downtown Seattle]] is the busiest highway in Washington state, with a daily average of over 274,000 vehicles in the mainline and express lanes.<ref name="Times-Ease">{{cite news |last=Gutman |first=David |date=June 19, 2017 |title=Can't Washington state ease I-5 traffic? Fixes exist, but most of them are pricey. |url=https://www.seattletimes.com/seattle-news/transportation/cant-washington-state-ease-i-5-traffic-fixes-exist-but-most-of-them-are-pricey/ |work=[[The Seattle Times]] |access-date=June 14, 2018}}</ref> The least-traveled segment of I-5 is located at [[Washington State Route 548|SR&nbsp;548]] in [[Blaine, Washington|Blaine]], with a daily average of 6,600 vehicles.<ref>{{cite web |title=2016 Annual Traffic Report |pages=73–82 |url=http://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2016.pdf |publisher=Washington State Department of Transportation |access-date=June 14, 2018 |archive-date=August 12, 2017 |archive-url=https://web.archive.org/web/20170812180326/http://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2016.pdf }}</ref> I-5 through the [[Seattle metropolitan area]] is among the worst congested highways in the United States, with 78 percent of peak direction miles classified as "routinely congested" for seven to eight hours a day and an average annual delay of 55 hours for Seattle–[[Everett, Washington|Everett]] commutes.<ref>{{cite news |last=Lindblom |first=Mike |date=February 5, 2018 |title=It's worse than you think: Everett leads the nation in traffic congestion, report says |url=https://www.seattletimes.com/seattle-news/transportation/its-worse-than-you-think-everett-leads-the-nation-in-traffic-congestion-report-says/ |work=The Seattle Times |access-date=June 17, 2018}}</ref><ref>{{cite web |date=December 2017 |title=2017 Corridor Capacity Report |pages=11–14 |url=http://wsdot.wa.gov/publications/fulltext/graynotebook/corridor-capacity-report-17.pdf |publisher=Washington State Department of Transportation |access-date=June 17, 2018}}</ref><ref>{{cite news |last=Gutman |first=David |date=June 19, 2017 |title=Here's why I-5 is such a mess in Seattle area, and what keeps us moving at all |url=https://www.seattletimes.com/seattle-news/transportation/heres-why-i-5-is-such-a-mess-in-seattle-area-and-what-keeps-us-moving-at-all/ |work=The Seattle Times |access-date=June 17, 2018}}</ref> The freeway has a maximum [[speed limit]] of {{convert|70|mph|kph}} in rural areas and {{convert|60|mph|kph|abbr=on}} in urban and suburban areas, which includes a {{convert|100|mi|km|adj=mid}} section between [[Tumwater, Washington|Tumwater]] and [[Marysville, Washington|Marysville]].<ref name="log"/><ref>{{cite news |last=Dietrich |first=William |date=April 30, 2006 |title=Lynnwood Redux: Where else will 100,000 newcomers a year go now? |page=16 |url=https://archive.seattletimes.com/archive/20060428/pacificpchange30/lynnwood-redux |work=The Seattle Times |access-date=June 30, 2018}}</ref>

===Southwestern Washington===
[[File:Amtrak Cascades in I-5 median, April 2010.jpg|thumb|left|An [[Amtrak Cascades|Amtrak ''Cascades'']] train running in the median of I-5 near [[Kalama, Washington|Kalama]]. The route of the ''Cascades'' generally runs parallel to I-5 within Washington state.]]

I-5 enters Washington on the [[Interstate Bridge]], a pair of [[vertical-lift bridge]]s that span the [[Columbia River]] between Portland, Oregon, and Vancouver, Washington. The bridge is the only point on I-5 where vehicles have to stop for cross traffic, because of the lifts.<ref>{{cite news |last=Pesanti |first=Dameon |date=February 12, 2017 |title=Interstate Bridge turns 100: 'With Iron Bands,' a century spanned |url=http://www.columbian.com/news/2017/feb/12/interstate-bridge-turns-100-with-iron-bands-a-century-spanned/ |work=The Columbian |access-date=June 14, 2018}}</ref> On the north bank of the river, the freeway passes under a railroad viaduct carrying Amtrak's ''[[Empire Builder]]'' and intersects [[Washington State Route 14|SR&nbsp;14]]. The interchange with SR&nbsp;14, located west of [[Pearson Field]] and the [[Fort Vancouver National Historic Site]], also includes ramps serving downtown Vancouver.<ref>{{cite web |date=June 9, 2016 |title=SR 5 – Exit 1A/1B: Junction SR 14 |url=https://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X001A.pdf |publisher=Washington State Department of Transportation |access-date=June 14, 2018}}</ref><ref>{{cite map |title=Downtown Vancouver Walking Map |url=http://www.cityofvancouver.us/sites/default/files/fileattachments/community_and_economic_development/page/1455/walkingmapweb.pdf |publisher=City of Vancouver |access-date=June 14, 2018}}</ref> I-5 continues north through suburban Vancouver and into [[Hazel Dell, Washington|Hazel Dell]], passing the [[Clark College]] campus and intersecting [[Washington State Route 501|SR&nbsp;501]] at Fourth Plain Boulevard and  [[Washington State Route 500|SR&nbsp;500]] at Burnt Bridge Creek. I-5 intersects [[Interstate 205 (Oregon–Washington)|I-205]], the eastern freeway bypass of the [[Portland metropolitan area]], in [[Salmon Creek, Washington|Salmon Creek]] near the [[Washington State University Vancouver|Vancouver campus]] of [[Washington State University]].<ref name="googlemaps">{{google maps |title=Interstate 5, Washington |url=https://www.google.com/maps/dir/45.6185176,-122.6747647/49.002084,-122.7560189/@47.2926398,-124.5050314,7z/am=t/data=!4m2!4m1!3e0?shorturl=1 |access-date=June 14, 2018}}</ref>

From Salmon Creek, I-5 continues northwesterly and intersects [[Washington State Route 502|SR&nbsp;502]] at the Gee Creek [[rest area]] west of [[Battle Ground, Washington|Battle Ground]].<ref>{{cite news |last=Florip |first=Eric |date=October 8, 2014 |title=Rest area rebuild expands Gee Creek site |url=http://www.columbian.com/news/2014/oct/08/rest-area-gee-creek-site-interstate-5/ |work=The Columbian |access-date=June 14, 2018}}</ref> Its next interchange, in eastern [[Ridgefield, Washington|Ridgefield]], forms the eastern terminus of SR&nbsp;501. The freeway passes the [[Ilani Casino Resort]] on the [[Cowlitz Indian Tribe|Cowlitz reservation]] and crosses the [[Lewis River (Washington)|Lewis River]] into [[Woodland, Washington|Woodland]], where it intersects [[Washington State Route 503|SR&nbsp;503]]. Northwest of Woodland, the [[median strip|median]] of I-5 is used by freight trains and Amtrak's ''Cascades'' and ''[[Coast Starlight]]'' passenger trains, which follow the freeway for its entire length.<ref name="WSDOT-PassengerRail">{{cite map |date=January 2012 |title=Passenger Rail System, Washington State |url=https://www.wsdot.wa.gov/NR/rdonlyres/55697D20-A6E8-4544-A680-AE8889934FFB/0/PassengerRailSystemStations.pdf |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20170222014503/http://www.wsdot.wa.gov/nr/rdonlyres/55697d20-a6e8-4544-a680-ae8889934ffb/0/passengerrailsystemstations.pdf |archive-date=February 22, 2017 |access-date=June 14, 2018}}</ref><ref>{{cite web |date=October 12, 2011 |title=SR 5 – Exit 22: Junction Dike Access Road |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X022.pdf |publisher=Washington State Department of Transportation |access-date=June 14, 2018}}</ref> I-5 continues along the east bank of the Columbia River, passing through [[Kalama, Washington|Kalama]] on the way towards [[Longview, Washington|Longview]] and [[Kelso, Washington|Kelso]]. At the south end of Kelso, near the confluence of the Columbia and [[Cowlitz River|Cowlitz]] rivers, the freeway intersects [[Washington State Route 432|SR&nbsp;432]], which connects to Longview and the [[Lewis and Clark Bridge (Columbia River)|Lewis and Clark Bridge]] via [[Washington State Route 433|SR&nbsp;433]]. I-5 continues north along the [[Coweeman River]] to the [[Three Rivers Mall]], located east of downtown Kelso, where [[Washington State Route 4|SR&nbsp;4]] terminates.<ref name="googlemaps"/> Between Vancouver and Kelso, the highway is part of the [[Lewis and Clark Trail]], a state scenic highway that continues west along SR&nbsp;4 towards the [[Pacific Ocean]].<ref name="WSDOTMap"/><ref>{{cite web |title=Lewis and Clark Trail Scenic Byway |url=http://www.wsdot.wa.gov/LocalPrograms/ScenicByways/LewisAndClark.htm |publisher=Washington State Department of Transportation |access-date=June 14, 2018 |archive-url=https://web.archive.org/web/20141023065333/http://www.wsdot.wa.gov/LocalPrograms/ScenicByways/LewisAndClark.htm |archive-date=October 23, 2014 |df=mdy-all }}</ref>

The freeway continues north, following the Cowlitz River to [[Castle Rock, Washington|Castle Rock]], where it meets [[Washington State Route 411|SR&nbsp;411]] and a short [[Business routes of Interstate 5|business route]] that loops back to an interchange with [[Washington State Route 504|SR&nbsp;504]], the main highway to [[Mount St. Helens]].<ref>{{cite news |last=LaBoe |first=Barbara |date=September 5, 2006 |title=Castle Rock hopes to catch travelers' eyes with new signs |url=https://tdn.com/business/local/castle-rock-hopes-to-catch-travelers-eyes-with-new-signs/article_30155c57-b39c-528a-a4c3-55a94bb56799.html |work=[[The Daily News (Longview)|The Daily News]] |location=Londview, Washington |access-date=July 13, 2020}}</ref> North of Castle Rock, the Cowlitz River turns away from I-5 as the latter enters [[Lewis County, Washington|Lewis County]], intersecting [[Washington State Route 506|SR&nbsp;506]] west of [[Toledo, Washington|Toledo]] and [[Washington State Route 505|SR&nbsp;505]] east of [[Winlock, Washington|Winlock]]. Between the two interchanges is the [[Gospodor Monument Park]], a [[roadside attraction]] with four sculptures of up to {{convert|100|ft|m}} in height commemorating religious and indigenous figures.<ref>{{cite news |last=Richard |first=Terry |date=March 25, 2009 |title=I-5 eye catcher: Gospodor Monument at Toledo |url=http://blog.oregonlive.com/terryrichard/2009/03/i5_eye_catcher_gospodors_monum.html |work=[[The Oregonian]] |access-date=September 11, 2018}}</ref> After their installation in 2002, the sculptures caused backups on the freeway due to [[rubbernecking]] by passing drivers who slowed down near them.<ref>{{cite news |last=Mittge |first=Brian |date=December 24, 2002 |title=Gospodor's monuments continue to affect traffic |page=A3 |work=[[The Chronicle (Centralia, Washington)|The Chronicle]] |location=Centralia, Washington}}</ref><ref>{{cite news |last=Anderson |first=Peggy |date=May 25, 2003 |title=Safety of motorists towers over debate about man's art |page=C9 |work=[[Statesman Journal]] |location=Salem, Oregon |agency=Associated Press |url=https://www.newspapers.com/clip/23655009/gospodors_monuments_in_toledo/ |via=[[Newspapers.com]] |access-date=September 11, 2018}}</ref> Near [[Napavine, Washington|Napavine]], I-5 becomes [[concurrency (road)|concurrent]] with [[U.S. Route 12 in Washington|US&nbsp;12]], which continues east across [[White Pass (Washington)|White Pass]] to [[Yakima, Washington|Yakima]].<ref name="WSDOTMap"/><ref name="googlemaps"/>

The two highways intersect [[Washington State Route 508|SR&nbsp;508]] and cross over the [[Newaukum River]] near the [[Uncle Sam billboard]], a politically conservative message board and roadside attraction.<ref>{{cite news |last=Kershaw |first=Sarah |date=November 28, 2004 |title=Highway's Message Board Now Without a Messenger |page=37 |url=https://www.nytimes.com/2004/11/28/us/highways-message-board-now-without-a-messenger.html |work=[[The New York Times]] |access-date=September 11, 2018}}</ref> I-5 and US&nbsp;12 turn northwest to follow the river and pass along the western edge of [[Chehalis, Washington|Chehalis]], where they intersect [[Washington State Route 6|SR&nbsp;6]]. After passing the [[Chehalis-Centralia Airport]], the freeway follows the [[Chehalis River (Washington)|Chehalis River]] to the western side of [[Centralia, Washington|Centralia]]. I-5 and US&nbsp;12 then intersect [[Washington State Route 507|SR&nbsp;507]] and gain a set of [[collector–distributor lane]]s as the freeway crosses the [[Skookumchuck River]] and a set of railroad tracks on the northwest side of the city. US&nbsp;12 leaves the concurrency at [[Grand Mound, Washington|Grand Mound]], heading west towards [[Aberdeen, Washington|Aberdeen]] while I-5 continues north into [[Thurston County, Washington|Thurston County]].<ref name="WSDOTMap"/><ref name="googlemaps"/>

===South Sound region===
[[File:I-5 southbound from S Yakima Avenue, Tacoma (20062541909).jpg|thumb|right|A section of I-5 near downtown [[Tacoma, Washington|Tacoma]], pictured in 2015 during an expansion project]]

North of Grand Mound, I-5 passes two interchanges with [[Washington State Route 121|SR&nbsp;121]], which forms a loop between two of the exits to serve [[Millersylvania State Park]]. The freeway travels through the suburb of Tumwater, passing the [[Olympia Regional Airport]] and several state [[office park]]s before reaching the terminus of [[U.S. Route 101 in Washington|US&nbsp;101]], a major highway that encircles the [[Olympic Peninsula]], on the south side of [[Capitol Lake]].<ref name="WSDOTMap"/> After the interchange, I-5 enters [[Olympia, Washington|Olympia]] and turns eastward after passing the [[Washington State Capitol]] campus and downtown Olympia. The freeway passes through [[Lacey, Washington|Lacey]] and the Hawks Prairie industrial area, where it intersects [[Washington State Route 510|SR&nbsp;510]], a highway serving the [[Nisqually Indian Community]] and [[Yelm, Washington|Yelm]].<ref name="WSDOTMap"/> I-5 continues northeast through the [[Billy Frank Jr. Nisqually National Wildlife Refuge]] towards [[DuPont, Washington|DuPont]] on the east side of the [[Nisqually River]] in [[Pierce County, Washington|Pierce County]].<ref name="googlemaps"/>

Immediately east of DuPont, I-5 travels through [[Joint Base Lewis–McChord]], a major military installation that encompasses land on both sides of the freeway and its [[Point Defiance Bypass|parallel railroad]]. Near [[American Lake]], an interchange with Thorne Lane marks the proposed western terminus of [[Washington State Route 704|SR&nbsp;704]], a new highway that would travel between the boundaries of [[Fort Lewis (Washington)|Fort Lewis]] and [[McChord Air Force Base]] (the two components of Joint Base Lewis–McChord) to [[Spanaway, Washington|Spanaway]].<ref>{{cite web |title=SR 704 - Cross Base Highway Project |url=https://www.wsdot.wa.gov/Projects/SR704/CrossBase/default.htm |publisher=Washington State Department of Transportation |access-date=June 14, 2018 |archive-date=June 15, 2018 |archive-url=https://web.archive.org/web/20180615055546/http://www.wsdot.wa.gov/Projects/SR704/CrossBase/default.htm |url-status=dead }}</ref> Continuing past the bases, I-5 passes through [[Lakewood, Washington|Lakewood]] and intersects [[Washington State Route 512|SR&nbsp;512]], a freeway connecting east to [[Puyallup, Washington|Puyallup]], before it reaches Tacoma.<ref name="googlemaps"/>

In Tacoma, the freeway passes the [[Tacoma Mall]], turns east, and splits into collector–distributor lanes that run through central Tacoma and serve two interchanges: the terminus of [[Washington State Route 16|SR&nbsp;16]], which continues northwest over the [[Tacoma Narrows Bridge]] to the [[Kitsap Peninsula]]; and [[Interstate 705|I-705]] and [[Washington State Route 7|SR&nbsp;7]], which serve downtown Tacoma, the [[Tacoma Dome]], [[Tacoma Dome Station]], and the Pacific Avenue corridor.<ref>{{cite news |last=Nunnally |first=Derrick |date=July 11, 2017 |title=Southbound I-5 will get local/express division in Tacoma |url=http://www.thenewstribune.com/news/local/traffic/article160611669.html |work=[[The News Tribune]] |location=Tacoma, Washington |access-date=June 14, 2018}}</ref> East of the Tacoma Dome area, I-5 intersects [[Washington State Route 167|SR&nbsp;167]] and crosses over the [[Puyallup River]] and a railroad carrying [[Sounder commuter rail|Sounder commuter trains]]. The freeway reaches [[Fife, Washington|Fife]] on the [[Puyallup Indian Reservation]] and intersects [[Washington State Route 99|SR&nbsp;99]], a section of former [[U.S. Route 99|US&nbsp;99]], at 54th Avenue East near the [[Emerald Queen Casino]]. After crossing Hylebos Creek, I-5 turns north and ascends from the Puyallup River Valley, entering [[King County, Washington|King County]] and the city of [[Federal Way, Washington|Federal Way]] while parallel to SR&nbsp;99.<ref name="googlemaps"/>

After passing under [[Washington State Route 161|SR&nbsp;161]] at Kitts Corner near the [[Wild Waves Theme Park]], I-5 intersects [[Washington State Route 18|SR&nbsp;18]], a freeway that connects to [[Auburn, Washington|Auburn]] and [[Maple Valley, Washington|Maple Valley]]. I-5 continues north past the [[Weyerhaeuser Corporate Headquarters|former corporate headquarters]] of [[Weyerhauser]] to central Federal Way, where the freeway's [[high-occupancy vehicle lane]]s (HOV lanes) have a direct off-ramp to the [[Federal Way Transit Center]] and [[The Commons at Federal Way]] shopping mall. The freeway travels north into western [[Kent, Washington|Kent]], intersecting [[Washington State Route 516|SR&nbsp;516]] near [[Highline College]]. North of [[Angle Lake (Washington)|Angle Lake]], I-5 tracks eastward between the cities of [[SeaTac, Washington|SeaTac]] and [[Tukwila, Washington|Tukwila]], passing east of [[Seattle–Tacoma International Airport]]. At the [[Westfield Southcenter]] shopping mall in Tukwila, I-5 intersects [[Washington State Route 518|SR&nbsp;518]], the primary means of access to the airport and [[Burien, Washington|Burien]], and [[Interstate 405 (Washington)|I-405]], the eastern freeway bypass of Seattle that travels through [[Renton, Washington|Renton]] and the Eastside. The interchange includes several left-hand ramps, necessitating the separation of the thru HOV lanes from the mainline.<ref>{{cite web |date=January 5, 2009 |title=SR 5 – Exit 154: Junction SR 405/SR 518 |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X154.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref> For a short distance, the [[light rail]] tracks of the [[1 Line (Sound Transit)|Link 1&nbsp;Line]], which followed SR&nbsp;518 from [[Tukwila International Boulevard station]], join I-5 and run on its west side until the next interchange at [[Washington State Route 599|SR&nbsp;599]], a short freeway that connects to SR&nbsp;99.<ref>{{cite map |last=Nowlin |first=Mark |date=July 12, 2009 |title=Your guide to riding light rail |work=The Seattle Times |url=http://seattletimes.nwsource.com/flatpages/local/lightrailinteractive.html |archive-url=https://web.archive.org/web/20090715003858/http://seattletimes.nwsource.com/flatpages/local/lightrailinteractive.html |archive-date=July 15, 2009 |access-date=June 15, 2018}}</ref> From the SR&nbsp;599 interchange, I-5 makes a gradual turn to the northwest while crossing over the [[Duwamish River]] and a mainline railroad, following the latter into the city of Seattle after an interchange with [[Washington State Route 900|SR&nbsp;900]].<ref name="WSDOTMap"/><ref name="googlemaps"/>

===Seattle and Shoreline===
{{anchor|Seattle}}
[[File:Seattle I-5 skyline dllu.jpg|left|thumb|I-5 and the [[Downtown Seattle]] skyline, as seen from [[Dr. Jose Rizal Park]] on [[Beacon Hill, Seattle|Beacon Hill]]]]

After entering Seattle, I-5 passes under the Link 1&nbsp;Line tracks at Boeing Access Road and runs northwesterly between [[Boeing Field]] and [[Georgetown, Seattle|Georgetown]] to the west along the railroad and [[Beacon Hill, Seattle|Beacon Hill]] to the east.<ref>{{cite news |date=November 24, 2006 |title=Your ride to airport is on the way |page=A1 |work=The Seattle Times}}</ref> Mid-way along Beacon Hill near [[Jefferson Park (Seattle)|Jefferson Park]], the freeway turns due north and intersects the east end of the Spokane Street Viaduct, part of the [[West Seattle Bridge]], which has additional ramps to the [[SoDo, Seattle|SoDo]] area and the [[VA Puget Sound Medical Center]].<ref name="googlemaps"/> I-5 continues north between SoDo and northern Beacon Hill, crossing over the western portal of the [[Beacon Hill tunnel (Seattle)|Beacon Hill light rail tunnel]] near 1&nbsp;Line's [[railyard]] and operating base.<ref>{{cite web |title=Beacon Hill Tunnel & Station |url=https://www.soundtransit.org/sites/default/files/documents/pdf/archived_projects/20121130_beaconhilltunnelandstation.pdf |publisher=[[Sound Transit]] |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20150909225511/http://www.soundtransit.org/sites/default/files/documents/pdf/archived_projects/20121130_beaconhilltunnelandstation.pdf |archive-date=September 9, 2015 |df=mdy-all }}</ref> At the north end of SoDo and Beacon Hill, I-5 intersects [[Interstate 90 in Washington|I-90]], the state's major east–west freeway, forming a large interchange with ramps to [[T-Mobile Park]] and [[Lumen Field]], two of the city's professional sports stadiums.<ref name="WSDOTMap"/><ref name="googlemaps"/>

North of the interchange, I-5 travels on an elevated viaduct over the [[International District, Seattle|International District]] and splits into collector–distributor lanes that serve exits to [[Downtown Seattle]]. The thirteen-lane freeway, among the widest in the United States,<ref>{{cite web |date=July 27, 2010 |title=Urban Highways with the Most Lanes |url=https://www.fhwa.dot.gov/policyinformation/tables/01.pdf |publisher=Federal Highway Administration |access-date=June 15, 2018}}</ref> runs in the [[city block|full block]] between 6th and 7th avenues between downtown to the west and [[First Hill, Seattle|First Hill]] to the east, home to [[Harborview Medical Center]] and [[Yesler Terrace, Seattle|Yesler Terrace]]. It passes to the east of Seattle's tallest building, the [[Columbia Center]],<ref>{{cite news |last=Duncan |first=Don |date=October 8, 1989 |title=Promises to keep: The sky's the limit |page=13 |work=The Seattle Times}}</ref> and the city's [[Seattle Central Library|Central Library]] before adding a set of [[Reversible express lanes in Seattle, Washington|reversible express lanes]] in the median near [[Madison Street (Seattle)|Madison Street]].<ref name="googlemaps"/> I-5 turns northeasterly and passes under two structures built atop sections of the highway: [[Freeway Park]], a landscaped city park between Seneca and Union streets; and the [[Seattle Convention Center]] between Union and Pike streets.<ref>{{cite news |last=Easton |first=Valerie |date=June 27, 2008 |title=In the concrete jungle, Freeway Park will offer respite once again |url=http://old.seattletimes.com/html/pacificnw/2008065997_pacificplife27.html |work=The Seattle Times |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20180616002034/http://old.seattletimes.com/html/pacificnw/2008065997_pacificplife27.html |archive-date=June 16, 2018 }}</ref><ref>{{cite news |last=Mahoney |first=Sally Gene |date=July 24, 1983 |title=Convention Center: Unveiled model gives a glimpse of how it may look |page=D6 |work=The Seattle Times}}</ref><ref>{{cite web |date=November 1, 2006 |title=Final List of Nationally and Exceptionally Significant Features of the Federal Interstate Highway System |url=https://www.environment.fhwa.dot.gov/env_topics/historic_pres/final_task4ListFinal.pdf |publisher=Federal Highway Administration |access-date=June 16, 2018 |archive-url=https://web.archive.org/web/20180616103814/https://www.environment.fhwa.dot.gov/env_topics/historic_pres/final_task4ListFinal.pdf |archive-date=June 16, 2018 }}</ref>

[[File:Over Lake Union.JPG|thumb|right|The [[Ship Canal Bridge]], which carries I-5 into the [[University District, Seattle|University District]] in Seattle]]

I-5 continues north out of downtown Seattle under a {{convert|20 to 30|ft|m|adj=mid}} [[retaining wall]] along Melrose Avenue at the edge of [[Capitol Hill (Seattle)|Capitol Hill]].<ref>{{cite news |last1=Barber |first1=Mike |last2=Wong |first2=Brad |last3=Murakami |first3=Kery |date=December 19, 2008 |title=Students screamed as bus crashed through I-5 barrier |url=https://www.seattlepi.com/local/article/Students-screamed-as-bus-crashed-through-I-5-1295375.php |work=Seattle Post-Intelligencer |access-date=June 15, 2018}}</ref> To the west is the [[South Lake Union, Seattle|South Lake Union]] and [[Cascade, Seattle|Cascade]] neighborhoods, accessed via ramps to Stewart Street and [[Mercer Street (Seattle)|Mercer Street]]. The freeway travels along the north end of Capitol Hill through the [[Eastlake, Seattle|Eastlake]] neighborhood on the east side of [[Lake Union]], passing over the [[I-5 Colonnade]] mountain bike park.<ref>{{cite news |last=McQuaide |first=Mike |date=September 25, 2008 |title=Flying high under I-5 at the new mountain bike park |page=H12 |url=http://old.seattletimes.com/html/outdoors/2008200171_nwwbikepark250.html |work=The Seattle Times |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20180616002053/http://old.seattletimes.com/html/outdoors/2008200171_nwwbikepark250.html |archive-date=June 16, 2018 }}</ref> At [[Roanoke Park (Seattle)|Roanoke Park]], I-5 intersects the western terminus of [[Washington State Route 520|SR&nbsp;520]], a major freeway that crosses [[Lake Washington]] on the [[Evergreen Point Floating Bridge (2016)|Evergreen Point Floating Bridge]] to Bellevue and [[Redmond, Washington|Redmond]].<ref name="googlemaps"/> The heavily trafficked Mercer Street and SR&nbsp;520 exits use ramps that are on opposite sides of the freeway, causing vehicles to weave across several lanes that contributes to traffic congestion.<ref>{{cite news |last=Lindblom |first=Mike |date=February 8, 2018 |title=More traffic lights on Mercer Street: Ramp-metering signals coming to I-5 onramps |url=https://www.seattletimes.com/seattle-news/transportation/more-traffic-lights-on-mercer-street-ramp-metering-signals-coming-to-i-5-onramps/ |work=The Seattle Times |access-date=July 9, 2018}}</ref><ref>{{cite news |last=Robinson |first=Herb |date=May 3, 1968 |title=Freeway 'Friction' Develops |page=A |work=The Seattle Times}}</ref>

I-5 continues onto the [[Ship Canal Bridge]] towards the [[University District, Seattle|University District]], crossing {{convert|160|ft|m}} over a section of the [[Lake Washington Ship Canal]] and Eastlake Avenue parallel to the [[University Bridge (Seattle)|University Bridge]]. The bridge also includes a lower deck for the express lanes, with a ramp connecting to Northeast 42nd Street in the University District.<ref>{{cite news |last1=Clarridge |first1=Christine |last2=Birkland |first2=Dave |date=August 29, 2001 |title=A day of despair, anger on I-5 – Woman survives plunge; commute halted 3-1/2 hours |page=A1 |work=The Seattle Times}}</ref><ref>{{cite news |last1=Birkland |first1=Dave |last2=Nalder |first2=Eric |last3=Andrews |first3=Paul |date=May 14, 1993 |title=Driver escapes dangling truck – with fiery cab hanging off I-5, trucker unhurt |page=C1 |work=The Seattle Times}}</ref>

I-5 runs north along 5th Avenue through the University District, a few blocks west of the [[University of Washington]] campus, and intersects Northeast 45th and 50th streets using a weaved pair of [[diamond interchange]]s.<ref>{{cite web |date=August 9, 2010 |title=SR 5 – Exit 169: Junction NE 45th Street/NE 50th Street |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X169.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref> In the [[Roosevelt, Washington|Roosevelt]]–[[Green Lake, Seattle|Green Lake]] area, I-5 intersects Ravenna Boulevard and [[Washington State Route 522|SR&nbsp;522]], a major highway that travels along the north side of Lake Washington.<ref name="WSDOTMap"/> Further north, the freeway reaches [[Northgate, Seattle|Northgate]] and the express lanes merge back with the mainline, forming a set of HOV lanes.<ref>{{cite news |last=Foster |first=George |date=October 21, 2001 |title=Getting There: Now you see the lane ... |url=https://www.seattlepi.com/local/transportation/article/Getting-There-Now-you-see-the-lane-1069476.php |work=Seattle Post-Intelligencer |access-date=June 15, 2018}}</ref> I-5 passes to the west of [[Northgate Mall (Seattle)|Northgate Mall]] and the [[Northgate station (Sound Transit)|Northgate light rail station]] along 1st Avenue before moving back east to 5th Avenue near [[Haller Lake, Seattle|Haller Lake]].<ref>{{cite news |last=Miller |first=Brian |date=November 8, 2017 |title=TOD proposals due for Northgate Station; city is seeking an upzone |url=http://www.djc.com/news/re/12105929.html |work=[[Seattle Daily Journal of Commerce]] |access-date=June 15, 2018}}</ref> At [[Jackson Park (Seattle)|Jackson Park]], freeway intersects [[Washington State Route 523|SR&nbsp;523]], which runs on 145th Street and forms the northern [[city limit]] of Seattle. The interchange includes a set of [[flyer stop]]s that are connected to SR&nbsp;523 by a northbound loop ramp and southbound slip ramp.<ref>{{cite web |date=February 7, 2011 |title=SR 5 – Exit 175: Junction SR 523/NE 145th Street |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X175.pdf |publisher=Washington State Department of Transportation |access-date=July 28, 2018}}</ref> I-5 continues north through [[Shoreline, Washington|Shoreline]], passing the [[King County Metro]] north bus base and several suburban neighborhoods before reaching [[Snohomish County, Washington|Snohomish County]].<ref name="googlemaps"/>

===Snohomish County===
[[File:Interstate 5 northbound in Lynnwood, WA.jpg|thumb|right|View of northbound I-5 in [[Lynnwood, Washington|Lynnwood]]]]

At the county line near [[Lake Ballinger]], I-5 intersects [[Washington State Route 104|SR&nbsp;104]], a highway that connects to [[Lake Forest Park, Washington|Lake Forest Park]], [[Edmonds, Washington|Edmonds]], and the Kitsap Peninsula via the [[Edmonds–Kingston ferry]].<ref name="WSDOTMap"/> The freeway continues through western [[Mountlake Terrace, Washington|Mountlake Terrace]], passing the [[Mountlake Terrace Transit Center]] and its median bus station near 236th Street Southwest. Upon entering [[Lynnwood, Washington|Lynnwood]], I-5 turns northeast and follows the [[Interurban Trail (Snohomish County)|Interurban Trail]], passing the [[Lynnwood Transit Center]], which is connected to the HOV lanes via a set of direct ramps.<ref>{{cite news |last=Hadley |first=Jane |date=November 16, 2004 |title=State opens direct-access ramps to I-5 at Lynnwood Transit Center |url=http://www.seattlepi.com/local/transportation/article/State-opens-direct-access-ramps-to-I-5-at-1159691.php |work=Seattle Post-Intelligencer |access-date=June 15, 2018}}</ref> The freeway then intersects [[Washington State Route 524|SR&nbsp;524]] (196th Street Southwest) and its [[spur route]] on 44th Avenue West before heading towards [[Alderwood Mall]]. To the east of the mall, I-5 intersects I-405 and [[Washington State Route 525|SR&nbsp;525]].<ref name="googlemaps"/>

I-5 crosses into northern Lynnwood and intersects 164th Street Southwest near [[Martha Lake, Washington|Martha Lake]] and [[Mill Creek, Washington|Mill Creek]], where a partial HOV ramp connects to the [[Ash Way Park and Ride]].<ref>{{cite web |date=August 29, 2017 |title=SR 5 – Exit 183: Junction 164th Street SW |url=https://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X183.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref> The freeway continues north into Everett and intersects [[Washington State Route 96|SR&nbsp;96]] southeast of [[Paine Field]]. It then passes [[Silver Lake (Everett, Washington)|Silver Lake]] and the South Everett park and ride (located in the freeway's median) at 112th Street Southeast near the [[Everett Mall]] and a southbound-only rest area.<ref>{{cite news |last=Nohara |first=Yoshiaki |date=September 12, 2008 |title=Soon, you'll be able to hop on a bus in the I-5 median |url=https://www.heraldnet.com/news/soon-youll-be-able-to-hop-on-a-bus-in-the-i-5-median/ |work=[[The Everett Herald]] |access-date=June 15, 2018}}</ref><ref>{{cite web |title=Safety rest area locations |url=https://www.wsdot.wa.gov/Safety/RestAreas/locations |publisher=Washington State Department of Transportation |access-date=June 15, 2018 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612044032/http://www.wsdot.wa.gov/Safety/RestAreas/locations }}</ref> Northeast of the mall, I-5 comes to a major interchange with several highways: SR&nbsp;99, which travels southwest as Everett Mall Way; [[Washington State Route 526|SR&nbsp;526]], which travels west to the [[Boeing Everett Factory]] and [[Mukilteo, Washington|Mukilteo]]; [[Washington State Route 527|SR&nbsp;527]], which travels south through Mill Creek; and Broadway, which continues north into downtown Everett.<ref name="WSDOTMap"/><ref>{{cite web |date=January 13, 2013 |title=SR 5 – Exit 189: Junction SR 99/SR 526/SR 527 |url=https://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X189.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref> From the mall interchange, I-5 descends towards the [[Lowell, Everett, Washington|Lowell]] area on the east side of a hill with several suburban neighborhoods. Near the [[Everett Memorial Stadium]] and Lowell Park, the freeway intersects 41st Street in a [[single-point urban interchange]], with additional ramps from the HOV and mainline lanes towards downtown Everett on Broadway.<ref>{{cite web |date=July 20, 2016 |title=SR 5 – Exit 192: Junction 41st Street/Old SR 529/Broadway Avenue |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X192.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref><ref>{{cite news |last=Nohara |first=Yoshiaki |date=September 30, 2008 |title=Everett finishing work on link to I-5 |url=https://www.heraldnet.com/news/everett-finishing-work-on-link-to-i-5/ |work=The Everett Herald |access-date=June 15, 2018}}</ref>

I-5 then curves northeasterly around downtown Everett, following the general course of the [[Snohomish River]], and intersects the southern terminus of [[Washington State Route 529|SR&nbsp;529]] at a half-diamond interchange with Pacific Avenue and Maple Street near the [[Everett Station|Everett train station]] and transit center. One block north of the interchange, the freeway intersects [[U.S. Route 2 in Washington|US&nbsp;2]], a major highway that travels across [[Stevens Pass]] to eastern Washington.<ref name="WSDOTMap"/> To the north of the US&nbsp;2 ramps is a second half-diamond interchange with [[Washington State Route 529 Spur|SR&nbsp;529 Spur]] on Everett Avenue, at which point the HOV lanes terminate and leave the freeway at six total lanes.<ref>{{cite web |date=June 3, 2011 |title=SR 5 – Exit 193/194: Junction Pacific Avenue/SR 2/SR 529 |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X193.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref><ref>{{cite web |date=November 2007 |title=I-5 – Everett HOV Freeway Expansion Project |url=http://www.wsdot.wa.gov/NR/rdonlyres/A60EC952-B6B1-4991-8430-C79505484B48/0/I5_EverettfolioNov2007.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20170221092626/http://www.wsdot.wa.gov/NR/rdonlyres/A60EC952-B6B1-4991-8430-C79505484B48/0/I5_EverettfolioNov2007.pdf |archive-date=February 21, 2017 }}</ref> I-5 continues north through a narrow trench in the Riverside neighborhood and passes Summit Park, a city park built using leftover land and excavated dirt from the freeway's construction.<ref name="googlemaps"/><ref>{{cite book |last1=May |first1=Allan |last2=Preboski |first2=Dale |year=1989 |title=The History of Everett Parks: A Century of Service and Vision |page=50 |publisher=[[The Donning Company]] |location=Norfolk, Virginia |isbn=0-89865-794-6 |oclc=20453314}}</ref>

The freeway continues over the Snohomish River and descends into the river's [[estuary]], which has several [[slough (hydrology)|slough]]s that I-5 crosses.<ref>{{cite web |year=1999 |title=Snohomish River Estuary Recreation Guide |url=https://snohomishcountywa.gov/DocumentCenter/View/19499/Estuary-Guide |publisher=Snohomish County Parks and Recreation |archive-url=https://web.archive.org/web/20180616080356/https://snohomishcountywa.gov/DocumentCenter/View/19499/Estuary-Guide |archive-date=June 16, 2018 |access-date=June 15, 2018}}</ref> It also passes the [[Everett Water Pollution Control Facility]] and several [[wastewater treatment]] ponds, which produces strong odors that are noted by motorists.<ref>{{cite news |last=Tuinstra |first=Rachel |date=March 24, 2004 |title=Go ahead, take a deep breath |page=H13 |url=https://archive.seattletimes.com/archive/20040324/stinky24n/go-ahead-take-a-deep-breath |work=The Seattle Times |access-date=June 15, 2018}}</ref> On the north side of Steamboat Slough, I-5 turns northwesterly and intersects SR&nbsp;529 before crossing over the [[BNSF Railway]] and Ebey Slough into Marysville. Within Marysville, the freeway runs due north along the boundary between the city and the [[Tulalip Indian Reservation]] and intersects several arterial streets:<ref>{{cite web |date=August 2010 |title=Tulalip Tribes Hazard Mitigation Plan 2010 Update, Section II: Community Profile |page=13 |url=https://www.tulaliptribes-nsn.gov/Portals/0/pdf/departments/emergency_management/2010-plan/TulalipHMP2010Sec2.pdf |publisher=[[Tulalip Tribes]] |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20170126044813/https://www.tulaliptribes-nsn.gov/Portals/0/pdf/departments/emergency_management/2010-plan/TulalipHMP2010Sec2.pdf |archive-date=January 26, 2017 }}</ref> [[Washington State Route 528|SR&nbsp;528]] west of downtown Marysville, 88th Street near [[Quil Ceda Village]], and 116th Street near the [[Tulalip Resort Casino]] and [[Seattle Premium Outlets]] shopping mall.<ref name="googlemaps"/><ref>{{cite news |last=Winters |first=Chris |date=November 25, 2015 |title=Bridge over I-5 enters final phases |url=https://www.heraldnet.com/news/bridge-over-i-5-enters-final-phases/ |work=The Everett Herald |access-date=June 15, 2018}}</ref>

North of the city and reservation, I-5 crosses over the railroad and enters [[Arlington, Washington|Arlington]]'s [[Smokey Point, Washington|Smokey Point]] neighborhood, where it intersects [[Washington State Route 531|SR&nbsp;531]] just west of [[Arlington Municipal Airport (Washington)|Arlington Municipal Airport]]. A pair of rest areas are situated north of the interchange and are the busiest in the state, serving 2.1&nbsp;million visitors per year, and is home to a {{convert|22|ft|m|adj=mid|-wide}} [[Western red cedar]] stump that was once hollowed out to allow vehicles to drive through it.<ref>{{cite news |last=Whitley |first=Peyton |date=August 6, 2003 |title=Rest areas: I-5 asylums |page=H20 |url=https://archive.seattletimes.com/archive/20030806/rest06n/rest-areas-i-5-asylums |work=The Seattle Times |access-date=June 15, 2018}}</ref><ref>{{cite news |last=Barr |first=Robert A. |date=July 5, 1970 |title=Marysville Stump Dates Back to Caesar |page=G5 |work=The Seattle Times}}</ref> The area around the freeway transforms from suburban to rural, with rolling hills and forested areas, as it approaches Island Crossing and an interchange with [[Washington State Route 530|SR&nbsp;530]] west of downtown Arlington. North of Island Crossing, I-5 crosses the [[Stillaguamish River]] and passes the [[Stillaguamish Indian Reservation]] and the [[Angel of the Winds Casino Resort]]. The freeway continues northwest through rural Snohomish County and intersects [[Washington State Route 532|SR&nbsp;532]] east of [[Stanwood, Washington|Stanwood]] before crossing into [[Skagit County, Washington|Skagit County]].<ref name="googlemaps"/>

===Skagit and Whatcom counties===
[[File:Peace Arch, U.S.-Canada border.jpg|thumb|right|The [[Peace Arch]] monument on the [[Canada–United States border|Canadian border]] marks where I-5 enters [[British Columbia]] as [[British Columbia Highway 99|Highway 99]]]]

From the Snohomish County line, the freeway turns north and descends into the [[Skagit Valley]] from Conway Hill, following the [[Skagit River]] that runs to its west. At [[Conway, Washington|Conway]], I-5 intersects [[Washington State Route 534|SR&nbsp;534]] and is joined by the BNSF railroad while continuing north towards [[Mount Vernon, Washington|Mount Vernon]]. The freeway narrows to four lanes within Mount Vernon and forms the boundary between the uphill suburban neighborhoods and downtown along the river. In downtown Mount Vernon, it intersects [[Washington State Route 536|SR&nbsp;536]] in an interchange adjacent to the [[Skagit Station|city's train station]]. At its next interchange, I-5 crosses the railroad and encounters [[Washington State Route 538|SR&nbsp;538]], which connects the freeway to the [[Skagit Valley College]] and a minor retail corridor.<ref name="googlemaps"/> The freeway then crosses the Skagit River into [[Burlington, Washington|Burlington]] on a bridge that [[I-5 Skagit River Bridge collapse|partially collapsed]] on May 23, 2013, and was subsequently renamed the Trooper Sean M. O'Connell Jr. Memorial Bridge after a [[Washington State Patrol|state trooper]] who died while directing detour traffic during its rebuilding.<ref>{{cite news |last=Burton |first=Lynsi |date=May 23, 2014 |title=The Skagit River bridge, 1 year after collapse |url=https://www.seattlepi.com/local/article/The-Skagit-River-bridge-1-year-after-collapse-5501507.php |work=Seattle Post-Intelligencer |access-date=June 15, 2018}}</ref><ref>{{cite web |last=Long |first=Priscilla |date=September 16, 2013 |title=I-5 Skagit River Bridge at Mount Vernon collapses on May 23, 2013. |url=http://www.historylink.org/File/10584 |work=HistoryLink |access-date=June 15, 2018}}</ref>

On the north side of the river, I-5 skirts the western edge of Burlington, passing car dealerships and retail stores, including the [[Cascade Mall]] and an [[outlet mall]].<ref>{{cite news |last=Wanielista |first=Kera |date=March 4, 2016 |title=Burlington postpones marijuana zoning issue |url=https://www.goskagit.com/all_access/burlington-postpones-marijuana-zoning-issue/article_f533ccba-1c4f-5eda-b7dd-ae437754c006.html |work=[[Skagit Valley Herald]] |location=Mount Vernon, Washington |access-date=June 15, 2018 |archive-date=January 16, 2018 |archive-url=https://web.archive.org/web/20180116102519/https://www.goskagit.com/all_access/burlington-postpones-marijuana-zoning-issue/article_f533ccba-1c4f-5eda-b7dd-ae437754c006.html }}</ref><ref>{{cite news |last=Judd |first=Ron C. |date=December 26, 2003 |title=Burlington frets about its soul |page=B1 |url=https://archive.seattletimes.com/archive/20031226/burlington26m/burlington-frets-about-its-soul |work=The Seattle Times |access-date=June 15, 2018}}</ref> To the west of downtown Burlington, the freeway intersects [[Washington State Route 20|SR&nbsp;20]], a major state highway, in a [[partial cloverleaf interchange]] that includes several businesses inside the western loop.<ref>{{cite web |date=February 4, 2010 |title=SR 5 – Exit 230: Junction SR 20/Burlington/Anacortes |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X230.pdf |publisher=Washington State Department of Transportation |access-date=June 15, 2018}}</ref> SR&nbsp;20 continues west towards [[Anacortes, Washington|Anacortes]] and the Olympic Peninsula, and east through [[North Cascades National Park]] to the [[Okanogan Country]] as the North Cascades Highway. In northern Burlington, I-5 intersects the southern end of [[Washington State Route 11|SR&nbsp;11]], which provides access to the western [[Chuckanut Mountains]].<ref name="WSDOTMap"/> I-5 crosses the railroad and the [[Samish River]] before reaching the [[Skagit Casino Resort]] and [[Skagit Speedway]] near [[Bow, Washington|Bow]] and [[Alger, Washington|Alger]], located in the middle of the heavily forested Chuckanut foothills. The freeway then travels up into the Chuckanut Mountains and crosses into [[Whatcom County, Washington|Whatcom County]] south of [[Lake Samish]].<ref name="googlemaps"/> The entire Skagit County section of I-5 is designated as the [[Skagit Valley Agricultural Scenic Corridor]], a [[Washington State Scenic and Recreational Highways|state scenic byway]], in recognition of its agricultural industry.<ref>{{cite news |last=Judd |first=Ron |date=April 21, 2013 |title=From wild birds to beet seeds, the Skagit Valley's riches are being kept safe |page=7 |url=http://seattletimes.com/html/pacificnw/2020743242_pacificpskagit21.html |work=The Seattle Times |access-date=August 30, 2018 |archive-url=https://web.archive.org/web/20130430102716/http://seattletimes.com/html/pacificnw/2020743242_pacificpskagit21.html |archive-date=April 30, 2013 }}</ref>

I-5 travels along the eastern shore of Lake Samish before turning west to follow Chuckanut Creek through a narrow valley formed by Chuckanut and Lookout mountains in [[Lake Samish State Park]]. At [[Lake Padden]], it turns north and enters the city of [[Bellingham, Washington|Bellingham]], intersecting SR&nbsp;11 east of [[Fairhaven, Washington|Fairhaven]] and the [[Alaska Marine Highway]] terminal.<ref name="WSDOTMap"/> The freeway travels along the east side of [[Sehome Hill]] and downtown, passing the [[Western Washington University]] campus and several intersections with downtown streets. Northeast of downtown Bellingham, I-5 intersects [[Washington State Route 542|SR&nbsp;542]] (the [[Mount Baker]] Highway) and turns west to meet [[Washington State Route 539|SR&nbsp;539]] at the [[Bellis Fair Mall]]. The freeway heads northwest and leaves Bellingham after passing [[Bellingham International Airport]], entering the predominately rural part of the [[Fraser Lowland]] region.<ref>{{cite web |date=February 2007 |title=Whatcom County Rural Land Study: A Collaborative Report Identifying Rural Areas of Agricultural Significance |pages=6–7 |url=http://www.co.whatcom.wa.us/DocumentCenter/View/4145/Rural-Lands-Study-Report-PDF |publisher=Whatcom County |archive-url=https://web.archive.org/web/20180616103358/http://www.co.whatcom.wa.us/DocumentCenter/View/4145/Rural-Lands-Study-Report-PDF |archive-date=June 16, 2018 |access-date=June 15, 2018}}</ref> I-5 continues northwest along the railroad, crossing the [[Nooksack River]] on a pair of [[truss bridge]]s near downtown [[Ferndale, Washington|Ferndale]] and reaching a junction with [[Washington State Route 548|SR&nbsp;548]] north of the city. SR&nbsp;548 continues along the highway and travels west towards the [[Cherry Point Refinery]] and [[Birch Bay, Washington|Birch Bay]].<ref name="googlemaps"/><ref>{{cite web |title=BP Cherry Point Revised Cogeneration Project Compensatory Mitigation Plan |year=2004 |page=21 |publisher=[[BP]] |url=https://books.google.com/books?id=aPkyAQAAMAAJ |via=[[Google Books]] |access-date=June 15, 2018}}</ref>

In Blaine, the northernmost city on I-5, [[Washington State Route 543|SR&nbsp;543]] splits off to serve an [[Pacific Highway Border Crossing|alternate border crossing]] for trucks and freight.<ref>{{cite news |date=June 23, 2008 |title=New signs show wait times at Canadian border |url=https://www.heraldnet.com/news/new-signs-show-wait-times-at-canadian-border/ |work=The Everett Herald |agency=Associated Press |access-date=June 15, 2018}}</ref> I-5 travels along the northeast edge of downtown Blaine and intersects SR&nbsp;548 before it reaches the [[Canada–United States border|Canadian border]] at the [[Peace Arch]], where the highway terminates.<ref name="googlemaps"/><ref name="GSAEIS"/> The monument was built in 1921 and its [[Peace Arch Park|surrounding park]] is open to the public without needing to report to [[customs]] officers.<ref>{{cite web |last=Dougherty |first=Phil |date=October 18, 2009 |title=Peace Arch Park (Blaine) |url=http://www.historylink.org/File/9194 |work=HistoryLink |access-date=June 15, 2018}}</ref> The park is connected to its administrative buildings and parking lots by a set of [[crosswalk]]s across the northbound and southbound lanes of Interstate 5.<ref name="GSAEIS">{{cite web |date=November 28, 2005 |title=Peace Arch Port of Entry Redevelopment Draft Environmental Impact Statement |page=3{{hyphen}}126 |publisher=[[General Services Administration]] |url=https://books.google.com/books?id=RUU3AQAAMAAJ |via=Google Books |access-date=June 15, 2018}}</ref> The [[Peace Arch Border Crossing|Peace Arch–Douglas crossing]] is the third-busiest port of entry on the Canadian border,<ref name="GSAEIS"/> with an average of 3,500 to 4,800 vehicles crossing per day.<ref>{{cite news |last=Heim |first=Kristi |date=February 9, 2009 |title=Border work at Peace Arch won't end in time for Olympics |page=A1 |url=http://old.seattletimes.com/html/olympics/2008723074_olyborder09.html |work=The Seattle Times |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20180616080600/http://old.seattletimes.com/html/olympics/2008723074_olyborder09.html |archive-date=June 16, 2018 }}</ref> The highway continues north as [[British Columbia Highway 99|Highway&nbsp;99]] towards Vancouver, located {{convert|30|mi|km}} northwest of Blaine.<ref>{{cite web |date=June 23, 2014 |title=Peace Arch Land Port of Entry |url=https://www.gsa.gov/cdnstatic/Building_Fact_Peace_Arch_Port_of_Entry_06-23-2014.pdf |publisher=General Services Administration |access-date=June 15, 2018}}</ref>

==Seattle express lanes==
{{anchor|Express lanes}}
[[File:I-5 express lanes northbound entrance at Seneca Street, Seattle (closed).jpg|thumb|right|The northbound mainline entrance to the express lanes at Seneca Street, with barriers and signage indicating its closure]]

I-5 has {{convert|7.14|mi|km}}<ref name="log"/> of [[Local-express lanes|express lanes]] within Seattle, which [[Reversible lane|reverse]] to carry traffic in the [[peak period|peak direction]]; the express lanes run in the median of the freeway between Downtown Seattle and Northgate, carrying 54,000 of the 270,000 vehicles on the Ship Canal Bridge on an average weekday, as measured in 2010.<ref>{{cite news |last=Lindblom |first=Mike |date=July 14, 2011 |title=State considers tolls for I-5 express lanes |page=A1 |url=http://old.seattletimes.com/html/localnews/2015603397_i5tolls14m.html |work=The Seattle Times |access-date=June 15, 2018 |archive-url=https://web.archive.org/web/20180616080516/http://old.seattletimes.com/html/localnews/2015603397_i5tolls14m.html |archive-date=June 16, 2018 }}</ref> The express lanes split from I-5 near James Street, with ramps to the mainline near the northbound Seneca Street exit; the southernmost downtown exit is at 5th Avenue and Cherry and Columbia streets under the [[Seattle Municipal Tower]] and adjacent to [[Seattle City Hall]].<ref>{{cite news |last=Lindblom |first=Mike |date=May 8, 2018 |title=Preparations for closure of transit tunnel lag |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/buses-could-be-evicted-from-the-downtown-bus-tunnel-next-spring-but-seattle-streets-might-not-be-ready/ |work=The Seattle Times |access-date=June 15, 2018}}</ref><ref>{{cite news |last=McDermott |first=Terry |date=May 7, 1989 |title=High-rise: Digging the hole – Latest skyscraper rises from one man's dream, another's financial pit |page=A1 |work=The Seattle Times}}</ref>

The express lanes run through downtown and the Cascade neighborhood on the lower deck of I-5's southbound lanes, with ramps to the Pike Street at 9th Avenue (including a former exit to [[Downtown Seattle Transit Tunnel]]'s [[Convention Place station]]), and Stewart and Howell streets at Eastlake Avenue.<ref name="WSDOT-ExpressMap">{{cite web |title=Express lanes |url=https://wsdot.wa.gov/travel/roads-bridges/express-lanes |publisher=Washington State Department of Transportation |access-date=October 10, 2022}}</ref><ref>{{cite news |last=Guillen |first=Tomas |date=September 26, 1990 |title=Sign at bus tunnel can't always be believed |page=A1 |work=The Seattle Times}}</ref> After the ramps from Mercer Street, the four-abreast express lanes emerge onto the median of I-5, following it past Capitol Hill and Eastlake to the Ship Canal Bridge. The express lanes cross the Ship Canal on the lower deck of the bridge, which includes an exit to Northeast 42nd Street in the University District. A southbound-only, HOV-only onramp from Ravenna Boulevard and an additional ramp to SR&nbsp;522 connect the express lanes to North Seattle, leaving two express lanes and an HOV lane. The express lanes end southwest of the Northgate Mall, with a ramp to Northeast 103rd Street and the two remaining lanes merging onto I-5.<ref name="googlemaps"/><ref name="WSDOT-ExpressMap"/> The downtown entrances at Cherry, Columbia, and Pike streets are designated for HOV use only to encourage carpooling without affecting buses using the ramps.<ref>{{cite news |date=February 3, 1984 |title=Hot line set against fast-lane cheaters |page=C16 |work=The Seattle Times}}</ref><ref>{{cite news |last=Lane |first=Bob |date=February 28, 1977 |title=Carpoolers gain route; Access to express lanes |page=A7 |work=The Seattle Times}}</ref><ref name="PI-Exits">{{cite news |last=Murakami |first=Kery |date=July 20, 2003 |title=Getting There: HOV exits are meant to discourage solo driving |url=https://www.seattlepi.com/news/article/Getting-There-HOV-exits-are-meant-to-discourage-1119780.php |work=Seattle Post-Intelligencer |access-date=June 15, 2018}}</ref>

The express lanes typically carry southbound traffic from 5&nbsp;a.m. to 11&nbsp;a.m. and northbound traffic from 11:15&nbsp;a.m. to 11&nbsp;p.m. on weekdays, with an overnight closure from 11&nbsp;p.m. to 5&nbsp;a.m. On most weekends, the lanes are open to southbound traffic from 8&nbsp;a.m. to 1:30&nbsp;p.m. and northbound traffic from 1:45&nbsp;p.m. to 11&nbsp;p.m., with an overnight closure to reduce neighborhood noise.<ref name="WSDOT-ExpressMap"/> The weekend times are sometimes adjusted for special events, including weekend sporting events, or construction on the mainline lanes in Seattle.<ref>{{cite web |year=2018 |title=I-5 Express Lane Operation on Weekends |url=https://www.wsdot.wa.gov/Northwest/King/ExpressLanes/Weekend.htm |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20180602032404/http://www.wsdot.wa.gov/Northwest/King/ExpressLanes/Weekend.htm |archive-date=June 2, 2018 |access-date=June 20, 2018}}</ref> The express lanes are controlled by a series of movable gates and electronic signs controlled by a remote operations center that relies on [[CCTV]] cameras and an inspection and sweep for abandoned vehicles by a ground crew, who also set up safety nets during the 15-minute switch-over.<ref name="WSDOT-X2012">{{cite press release |date=July 23, 2012 |title=Drivers save time and money with automated I-5 express lanes |url=http://www.wsdot.wa.gov/News/2012/07/23_AutomatedExpressLanes.htm |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20140710061336/http://www.wsdot.wa.gov/News/2012/07/23_AutomatedExpressLanes.htm |archive-date=July 10, 2014 |access-date=June 19, 2018 |df=mdy-all }}</ref><ref>{{cite news |last=Whitely |first=Peyton |date=October 28, 1990 |title=I-5 express lanes built to prevent bottlenecks |page=B1 |url=https://archive.seattletimes.com/archive/19901028/1100950/i-5-express-lanes-built-to-prevent-bottlenecks |work=The Seattle Times |access-date=June 20, 2018}}</ref> Prior to a $6.6&nbsp;million project to automate the gates and signage in 2012, the switch-over took 50 minutes in total.<ref name="WSDOT-X2012"/><ref>{{cite news |last=Lindblom |first=Mike |date=March 29, 2008 |title=Express-lane switch stuck in slow motion |url=http://old.seattletimes.com/html/localnews/2004314316_expresslanes29m.html |work=The Seattle Times |access-date=June 20, 2018 |archive-url=https://web.archive.org/web/20180620102305/http://old.seattletimes.com/html/localnews/2004314316_expresslanes29m.html |archive-date=June 20, 2018 }}</ref> During snowstorms and severe cold weather, WSDOT keeps the express lanes open in one direction for the entire day to prevent snow and ice from causing electronic failures in the automated gates.<ref>{{cite news |last=Lindblom |first=Mike |date=December 20, 2022 |title=How snow is affecting Seattle-area roads and transit |url=https://www.seattletimes.com/seattle-news/transportation/how-seattle-area-snow-is-impacting-transit-service/ |work=The Seattle Times |access-date=December 20, 2022}}</ref>

===Express lane exit list===
{{WAinttop|location=Seattle|county=King|length_ref=<ref name="log"/>}}
{{WAint
|mile=165.29
|road={{jct|state=WA|I|5|dir1=south|nolink1=y|city1=Tacoma|location2=[[Portland, Oregon|Portland]]}}
|notes=South end of express lanes}}
{{WAint
|mile=165.62
|road=5th Avenue, Columbia Street
|type=HOV
|notes=Southbound exit&nbsp;and northbound entrance (HOV only)}}
{{WAint
|mile=166.49
|road=Pike Street
|type=HOV
|notes=Southbound exit&nbsp;and northbound entrance (HOV only)}}
{{WAint
|mile=166.63
|road=Stewart Street&nbsp;– [[Downtown Seattle|Seattle City Center]]
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint
|mile=167.20
|mile2=167.26
|road=Mercer Street&nbsp;– [[Seattle Center]]
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint
|mile=168.96
|road=Northeast 42nd Street&nbsp;– [[University of Washington]]
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint
|mile=169.66
|road=Ravenna Boulevard
|type=HOV
|notes=Southbound entrance only (HOV only)}}
{{WAint
|mile=170.54
|road={{jct|state=WA|SR|522|name1=Lake City Way|city1=Bothell}}
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint
|mile=172.07
|road=Northeast 103rd Street, 1st Avenue Northeast
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint
|mile=172.43
|road={{jct|state=WA|I|5|dir1=north|nolink1=y|city1=Everett|location2=[[Vancouver|Vancouver, BC]]}}
|notes=North end of express lanes}}
{{jctbtm|keys=hov}}

==History==

===Early state and national highways===
{{imageframe|width=100|content=[[File:WA-PSH1.svg|100px]] [[File:US 99 (1961).svg|100px]]|caption=The shields for [[Primary State Highway 1 (Washington)|Primary State Highway 1]] and [[U.S. Route 99]], both predecessors of I-5|align=right}}

The [[Pacific Highway (U.S.)|Pacific Highway]] was formed in 1913 by the state government as the north–south trunk in its first highway system, following the general route of modern-day I-5.<ref name="HL-Ebey">{{cite web |last=Caldbick |first=John |date=March 23, 2012 |title=Ebey Slough Bridge (1925-2012) |url=http://www.historylink.org/File/10023 |work=HistoryLink |access-date=June 20, 2018}}</ref> The trunk route, one of three suggested by [[good roads]] activists for several years and studied by the state legislature in 1909,<ref name="HL-Ebey"/><ref>{{cite news |date=May 31, 1912 |title=Good Roads Association Outlines Great Highways |page=3 |work=[[Kennewick Courier]] |url=https://www.newspapers.com/clip/21019457/good_roads_trunk_highways/ |via=Newspapers.com |access-date=June 20, 2018}}</ref> strung together several [[wagon trail]]s dating back as early as the 1840s, when settlers arrived in the [[Puget Sound]] region from the [[Willamette Valley]] via the [[Cowlitz Trail]].<ref>{{cite news |date=March 1, 1962 |title=Another Trail |page=8 |work=[[Terre Haute Star]] |url=https://www.newspapers.com/clip/21146447/cowlitz_trail/ |via=Newspapers.com |access-date=June 20, 2018}}</ref> Part of the highway also followed the [[military road]] constructed in the 1850s from [[Fort Vancouver]] to [[Fort Bellingham]].<ref>{{cite news |last=McDonald |first=Lucile |author-link=Lucile Saunders McDonald |date=November 24, 1963 |title=Old Military Road Takes on a New Life |pages=4–5 |work=The Seattle Times}}</ref>

The Washington section was part of a longer highway along the West Coast from Canada to Mexico, which was conceived by the Pacific Highway Association of North America in 1910.<ref>{{cite news |date=September 20, 1910 |title=Autoists Organize Highway Association |page=9 |work=The Seattle Times}}</ref> The Pacific Highway was dedicated by 60,000 people at the Peace Arch in Blaine on September 4, 1923, with a few sections still under construction.<ref name="HL-Ebey"/> Earlier that year, the Washington state government had designated it as State Road 1 and allotted funds to pave some rural sections. By 1925, almost all of the highway had been paved or improved to modern standards.<ref name="HL-Ebey"/><ref>{{cite map |year=1925 |title=Rand McNally Official 1925 Auto Trails Map of Washington and Oregon |scale=1:1,077,120 |publisher=Rand McNally |url=http://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~2161~200067 |via=[[David Rumsey Historical Map Collection]] |access-date=July 25, 2018}}</ref>

The federal government and the [[American Association of State Highway Officials]] established a [[United States Numbered Highways|national highway system]] in 1926, designating most of the Pacific Highway north of [[Los Angeles]] as part of [[U.S. Route 99]] (US&nbsp;99).<ref>{{cite map |author1=[[Bureau of Public Roads]] |author2=[[American Association of State Highway Officials]] |date=November 11, 1926 |title=United States System of Highways Adopted for Uniform Marking by the American Association of State Highway Officials |url=https://commons.wikimedia.org/wiki/File:United_States_System_of_Highways_Adopted_for_Uniform_Marking_by_the_American_Association_of_State_Highway_Officials.jpg |scale=1:7,000,000 |location=Washington, DC |publisher=[[U.S. Geological Survey]] |oclc=32889555 |via=[[Wikimedia Commons]] |access-date=November 7, 2013}}</ref> The highway's Washington segment would ultimately be completed four years later with the opening of several bridges between Everett and Marysville.<ref name="HL-Ebey"/> It was also realigned in several areas to use newer cut-off roadways, bypassing older sections. The section between Burlington and Bellingham, historically on the water-facing [[Chuckanut Drive]], was moved inland via Lake Samish in 1931.<ref>{{cite news |date=August 21, 1931 |title=Samish, Skagit Highways Next, Humes Pledges |page=10 |work=The Seattle Times |agency=Associated Press}}</ref><ref>{{cite book |date=March 12, 1931 |title=Session Laws of the State of Washington, 1931 |chapter=Chapter 36: Pacific Highway |pages=107–108 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1931c36.pdf |publisher=Washington State Legislature |access-date=August 4, 2018}}</ref> State Road 1 was re-designated in 1937 as [[Primary State Highway 1 (Washington)|Primary State Highway 1]] under the state's new highway numbering system, but was not signed as such, giving priority to the overlapping US&nbsp;99.<ref>{{cite news |date=February 8, 1938 |title=George Washington's Head to Mark State Highways |page=13 |work=The Seattle Times}}</ref><ref>{{cite book |date=March 17, 1937 |title=Session Laws of the State of Washington, Twenty-Fifth Session |chapter=Chapter 190: Establishment of Primary State Highways |pages=933–943 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1937c190.pdf |publisher=Washington State Legislature |access-date=June 16, 2018}}</ref> By 1941, the Pacific Highway was the busiest road in the Pacific Northwest and had been widened to four lanes in most urban areas because of traffic congestion, necessitating studies into by-passing cities along the corridor.<ref>{{cite news |date=July 27, 1941 |title=Washington State Highways Traverse Scenic Wonderland |page=48 |work=The Seattle Times}}</ref><ref>{{cite news |date=June 30, 1938 |title=Alaskan Way By-Pass Asked |page=36 |work=The Seattle Times}}</ref>

===State upgrades and Interstate planning===

The federal government began planning for a national "superhighway" system in the late 1930s, including the US&nbsp;99 corridor as the main route along the West Coast.<ref>{{cite book |author=[[Bureau of Public Roads]] |date=April 27, 1939 |title=Toll Roads and Free Roads |page=19 |publisher=[[Government Printing Office]] |oclc=2843728 |url=https://catalog.hathitrust.org/Record/001611706 |via=[[HathiTrust]] |access-date=August 5, 2018}}</ref> The highway system, designed with a minimum of four lanes in rural areas and strict [[grade separation]], was approved for limited funding by Congress in 1944 and planned by the [[Bureau of Public Roads]] over the following years. The US&nbsp;99 corridor was included in the initial {{convert|37,700|mi|km|0|adj=mid}} system announced three years later by the [[Public Roads Administration]].<ref name="FHWA-Urban">{{cite web |last=Weingroff |first=Richard F. |title=Designating the Urban Interstates |url=https://www.fhwa.dot.gov/infrastructure/fairbank.cfm |publisher=Federal Highway Administration |access-date=August 5, 2018}}</ref>

The state legislature adopted its own set of standards for [[limited-access road|limited-access highway]]s in 1947, later amending them to encourage upgrades to existing two-lane roadways.<ref>{{cite web |last=Tate |first=Cassandra |date=November 8, 2004 |title=Washington Legislature authorizes construction of limited access highways in 1947. |url=http://www.historylink.org/File/7125 |work=HistoryLink |access-date=August 5, 2018}}</ref> In 1951, the legislature authorized a $66.7&nbsp;million [[bond issue]] (equivalent to ${{Format price|{{Inflation|US-GDP|66700000|1951}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} to fund upgrades to US&nbsp;99, including four-lane sections on all but {{convert|40|mi|km}} of the highway and a modern "[[freeway]]" through Vancouver.<ref>{{cite news |date=April 28, 1951 |title=State Outlines Plans for New Super-Highway |page=1 |work=The Daily Chronicle |location=Centralia, Washington |agency=Associated Press |url=https://www.newspapers.com/clip/22241479/us_99_superhighway_plan/ |via=Newspapers.com |access-date=August 5, 2018}}</ref> The plan was opposed by Governor [[Arthur B. Langlie]], who questioned its constitutionality on the basis that it could violate the state constitution's 18th amendment. The bond's use of future [[gas tax]] revenues to pay interest would, under some interpretations, violate the amendment's requirement that the gas tax must be used for highway purposes, using it instead to pay off debts.<ref>{{cite news |last=Cunningham |first=Ross |date=May 9, 1951 |title=Many Lawyers Back Langlie View That Highway Bond Issue Is Unconstitutional |page=10 |work=The Seattle Times}}</ref> Later that year, the [[Washington Supreme Court|state supreme court]] upheld the legislature's authorization and allowed the program to move forward.<ref>{{cite news |last=Cunningham |first=Ross |date=June 27, 1951 |title=Upholding Highway Bond Law Seen as Paving Way For Income-Tax O. K. |page=20 |work=The Seattle Times}}</ref> A separate bill in 1953 authorized planning for a [[toll road|toll highway]] between Tacoma and Everett to replace the nearly-complete [[Alaskan Way Viaduct]] and other urban streets with grade crossings and 19 total interchanges.<ref>{{cite news |last=Cunningham |first=Ross |date=February 3, 1952 |title=Knotty Financial, Traffic Problems Face Building Freeway Through Seattle |page=12 |work=The Seattle Times}}</ref><ref name="WANews-1967">{{cite news |last=Dugovich |first=William |date=May 1967 |title=Seattle's Superfreeway |pages=2–5 |work=Washington Highways |publisher=Washington State Department of Highways |volume=14 |issue=2 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/5246 |via=WSDOT Library Digital Collections |access-date=September 11, 2018}}</ref><ref>{{cite news |date=March 30, 1954 |title=85-Cent Charge On Everett-Tacoma Toll Road Recommended |page=1 |work=The Seattle Times}}</ref>

The upgrade program was divided into {{convert|226|mi|km}} of four-lane highway and {{convert|47|mi|km}} of two-lane highway in rural sections between Marysville and Blaine.<ref>{{cite news |last=Hittle |first=Leroy |date=May 21, 1953 |title=Paving Near Castle Rock Is Completed |page=28 |work=The Seattle Times}}</ref> Construction on the rural sections in southwestern Washington began in late 1951 and the first section near Kalama was opened early the following year.<ref>{{cite news |date=December 20, 1951 |title=Four-Lane Highway Near Kalama Due for Completion by January |page=9 |work=The Daily Chronicle |location=Centralia, Washington |url=https://www.newspapers.com/clip/22323200/kalama_highway_and_other_projects/ |via=Newspapers.com |access-date=August 6, 2018}}</ref><ref>{{cite news |date=February 15, 1952 |title=More Highway Will Be Paved |page=7 |work=The Daily Chronicle |location=Centralia, Washington |url=https://www.newspapers.com/clip/22323270/kalama_highway_paving/ |via=Newspapers.com |access-date=August 6, 2018}}</ref> Major bypasses of Centralia, Fort Lewis, Kelso, Marysville, and Tumwater were completed in 1954.<ref>{{cite news |last=Patty |first=Stanton |date=October 31, 1954 |title=Highway Section Opens |page=22 |work=The Seattle Times}}</ref><ref>{{cite news |date=September 15, 1954 |title=New Highway Link Opened |page=1 |work=The Daily Chronicle |location=Centralia, Washington |url=https://www.newspapers.com/clip/22212039/chehaliscentralia_highway_opened/ |via=Newspapers.com |access-date=August 6, 2018}}</ref><ref name="WANews-1957">{{cite news |date=March 1957 |title=Fort Lewis Bottlenecks To Be Broken |pages=8–9 |work=Washington Highways |publisher=Washington State Department of Highways |volume=6 |issue=9 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/2468/ |via=WSDOT Library Digital Collections |access-date=September 12, 2018}}</ref> The {{convert|2|mi|km|adj=mid|-long}} Vancouver freeway opened on April 1, 1955, constituting the state's first grade-separated freeway and costing $7&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|7000000|1955}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} to construct.<ref>{{cite news |date=April 1, 1955 |title=Traffic Flows on New Freeway |page=10 |work=[[Fairbanks News-Miner]] |agency=Associated Press |url=https://www.newspapers.com/clip/21536004/vancouver_freeway/ |via=Newspapers.com |access-date=August 6, 2018}}</ref> In December 1955, the section between Chehalis and Olympia was moved onto a straighter highway that bypassed [[Tenino, Washington|Tenino]] and other small towns along the meandering route of the Pacific Highway. Its opening marked the end of the southern section of the upgraded US&nbsp;99.<ref name="OLY-2008">{{cite news |last=Batcheldor |first=Matt |date=December 7, 2008 |title=I-5 at 50: It's changed the face of the region |page=A1 |work=The Olympian |url=https://www.newspapers.com/clip/119394703/i-5-at-50-its-changed-the-face-of-the/ |via=Newspapers.com |access-date=February 23, 2023}}</ref><ref>{{cite news |date=December 22, 1955 |title=New 4-Lane Link in '99' Is Opened |page=29 |work=The Seattle Times |agency=United Press International}}</ref> The northern section was declared complete after a bypass of Mount Vernon and Burlington, including a [[I-5 Skagit River Bridge collapse|new bridge]] over the [[Skagit River]], was opened to traffic in June 1957.<ref name="WANews-1958Aug">{{cite news |date=August 1958 |title=Construction for Busy U.S. 99 Begun Early; Much More Due in Future |pages=8–10 |work=Washington Highway News |publisher=Washington State Department of Highways |volume=8 |issue=1 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/3180/ |via=WSDOT Library Digital Collections |access-date=September 12, 2018}}</ref>

The [[Federal-Aid Highway Act of 1956]], signed into law by President [[Dwight D. Eisenhower]] on June 29, 1956, formally authorized the creation and majority-federal funding of the [[Interstate Highway System]].<ref name="FHWA-Urban"/> A few months later, the state supreme court overturned the $194&nbsp;million authorization (equivalent to ${{Format price|{{Inflation|US-GDP|194000000|1956}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} to build the {{convert|65|mi|km|adj=mid}} Tacoma–Everett expressway as a toll road after finding it to be unconstitutional. The federal contribution under the Interstate Highways program was anticipated to be $165&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|165000000|1956}}}} in {{Inflation-year|US-GDP}} dollars),{{inflation-fn|US-GDP}} but come in smaller installments that would require more time to complete the freeway project.<ref>{{cite news |last=Cunningham |first=Ross |date=December 5, 1956 |title=State High Court's Decision Means No Expressway Tolls |page=15 |work=The Seattle Times}}</ref> The entire US&nbsp;99 corridor was subsequently assigned the designation of "Interstate 5" in 1957 and the federal government allocated planning funds to begin engineering of the Seattle Freeway,<ref>{{cite news |last=Hittle |first=Leroy |date=October 9, 1957 |title=State's Two Major Highways To Be Renumbered In Defense System |page=1 |work=[[Port Angeles Evening News]] |agency=Associated Press |url=https://www.newspapers.com/clip/21044010/interstate_renumbering/ |via=Newspapers.com |access-date=August 6, 2018}}</ref> which commanded its own Highway Department division.<ref name="WANews-1967"/><ref>{{cite web |last=Becker |first=Paula |date=April 30, 2003 |title=First part of Seattle Freeway (Interstate 5) route receives federal funding on October 1, 1957. |url=http://www.historylink.org/File/4166 |work=HistoryLink |access-date=August 6, 2018}}</ref>

===Suburban and rural construction===
[[File:Bellingham, WA Alabama Street 5.JPG|thumb|right|I-5 was routed around downtown [[Bellingham, Washington|Bellingham]] and opened in 1960]]

Washington was the fastest of the three West Coast states to upgrade sections of US&nbsp;99 to four lanes and partial [[Interstate standard]]s using new interchanges, with only {{convert|15|mi|km}} of the highway in northern Whatcom County still two-laned by 1959.<ref>{{cite news |last=Jaques |first=Tom |date=October 4, 1959 |title=Engineers Closing Gaps in North-South Highway That Will Link Canada, Maxico; Washington Leads California, Oregon In Amount of Work Done |page=C1 |work=[[Eugene Register-Guard]] |url=https://www.newspapers.com/clip/21693498/interstate_5_overview_1959/ |via=Newspapers.com |access-date=September 11, 2018}}</ref> Among the first projects to use federal funding from the 1956 act was an upgrade of the Fort Lewis highway to four-lane freeway standards, which opened in September 1957 and included the relocation of the military base's main gate to a new [[cloverleaf interchange]].<ref>{{cite news |date=July 26, 1957 |title=Two Key Projects on Highway 99 Progress Rapidly |page=15 |work=The Seattle Times}}</ref><ref>{{cite news |date=October 1957 |title=New Fort Lewis Road Opened To Highway Traffic |page=24 |work=Washington Highway News |publisher=Washington State Department of Highways |volume=7 |issue=4 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/2851/ |via=WSDOT Library Digital Collections |access-date=September 11, 2018}}</ref> Another early Interstate project, the {{convert|6.5|mi|km|adj=mid}} Olympia Freeway, was opened to traffic on December 12, 1958, at a cost of $11.6&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|11600000|1958}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}} It also included a freeway section of US&nbsp;101 and US&nbsp;410 that intersected I-5 in the state's first three-level interchange.<ref>{{cite news |date=December 12, 1958 |title=Freeway Open in Olympia |page=1 |work=The Daily Chronicle |location=Centralia, Washington |agency=Associated Press |url=https://www.newspapers.com/clip/21693688/olympia_freeway_opens/ |via=Newspapers.com |access-date=September 12, 2018}}</ref> A rural section of freeway between Marysville and Mount Vernon was completed in early 1959.<ref>{{cite news |date=December 1958 |title=Four Lane Roadway Pushing North |page=14 |work=Washington Highway News |publisher=Washington State Department of Highways |volume=8 |issue=3 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/3135/ |via=WSDOT Library Digital Collections |access-date=September 12, 2018}}</ref>

The first section of the Tacoma–Seattle–Everett freeway was opened to traffic on October 1, 1959, extending the Fort Lewis freeway {{convert|5|mi|km}} from [[Gravelly Lake]] near [[McChord Field]] to South 72nd Street in southern Tacoma. The $4.68&nbsp;million project (equivalent to ${{Format price|{{Inflation|US-GDP|4680000|1959}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} built the six-lane freeway and a cloverleaf interchange at [[Secondary State Highway 5G (Washington)|SSH&nbsp;5G]] (now SR&nbsp;512).<ref>{{cite news |date=September 30, 1959 |title=1st Stretch of Freeway To Be Opened Tomorrow |page=20 |work=The Seattle Times}}</ref><ref>{{cite news |last=Stansfield |first=Dick |date=October 1, 1959 |title=Ceremony Opens New Freeway |page=1 |work=The News Tribune |url=https://www.newspapers.com/clip/98535046/ceremony-opens-new-freeway/ |via=Newspapers.com |access-date=March 27, 2022}}</ref> The Tacoma section was also the first to use the [[Interstate shield|Interstate highway shield]], which was installed during construction in 1958.<ref>{{cite news |date=March 9, 1958 |title=Sign of the times |page=43 |work=The Seattle Times}}</ref> By the end of 1959, new interchanges and overpasses had brought most of the highway between Vancouver and Olympia to Interstate standards.<ref>{{cite news |date=April 1959 |title=Interstate Construction Program Forging Ahead |pages=2–4 |work=Washington Highway News |publisher=Washington State Department of Highways |volume=8 |issue=5 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/3280/ |via=WSDOT Library Digital Collections |access-date=September 13, 2018}}</ref> Governor [[Albert D. Rosellini]] announced an accelerated push for freeway construction, primarily aimed at completing Interstate 5 between Seattle and the Canadian border, in August 1960.<ref>{{cite news |date=August 30, 1960 |title=Rosellini Will Push Freeway Projects |page=21 |work=The Seattle Times}}</ref>

The Tacoma section was extended {{convert|13.5|mi|km}} north to [[Midway, Washington|Midway]] (near Des Moines) on October 10, 1962. The dedication ceremony was attended by Governor Rosellini and included a parade of [[United States Army|U.S. Army]] vehicles from [[Fort Lewis (Washington)|Fort Lewis]]. The Tacoma–Midway section cost $14.5&nbsp;million to construct (equivalent to ${{Format price|{{Inflation|US-GDP|14500000|1951}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} and included a cloverleaf interchange for the Auburn cutoff (later SR&nbsp;18) in Federal Way.<ref>{{cite news |date=October 10, 1962 |title=Tacoma-Midway Link In Freeway Opened |page=1 |work=The Seattle Times}}</ref> The ceremony had been preceded by drivers trespassing onto the finished but unopened freeway a month earlier to avoid congestion on US&nbsp;99.<ref>{{cite news |last=Barr |first=Robert A. |date=September 25, 1962 |title='Sneaky' Drivers Use Yet-to-Open Freeway |page=1 |work=The Seattle Times}}</ref> The Tacoma and Olympia sections of I-5 were connected by a new freeway across Fort Lewis and the Nisqually River that opened in November 1968 and cost $12&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|12000000|1968}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}}<ref>{{cite news |last=Barr |first=Robert A. |date=March 5, 1968 |title=Interstate 5's Nisqually Flats Link to Be Opened by Autumn |page=17 |work=The Seattle Times}}</ref> Its opening eliminated the last traffic signal between Seattle and Portland.<ref>{{cite news |date=August 22, 1968 |title=Ft. Lewis-Lacey: Freeway Lanes To Open |page=7 |work=The Daily Chronicle |location=Centralia, Washington |url=https://www.newspapers.com/clip/23662391/ft-lewis-lacey-freeway/ |via=Newspapers.com |access-date=July 7, 2020}}</ref><ref>{{cite news |date=November 3, 1968 |title=Next-to-Last Freeway Link To Be Opened |page=37 |work=The Seattle Times}}</ref>

I-5 was routed around Bellingham on an easterly arc with several interchanges that were added after lobbying by downtown business groups who had originally favored a waterfront route.<ref>{{cite news |last=Vouri |first=Mike |date=July 21, 1986 |title=I-5's impact still being felt |page=B3 |work=The Bellingham Herald |url=https://www.newspapers.com/clip/89610184/i-5s-impact-still-being-felt/ |via=Newspapers.com |access-date=November 26, 2021}}</ref> The first section, {{convert|5|mi|km}} long and four lanes wide, opened to traffic on December 5, 1960, connecting with an existing expressway to Ferndale.<ref>{{cite news |last=Larson |first=Glenn |date=December 5, 1960 |title=Bellingham Freeway in Use: Ribbon Cut, Siren Blast Opens Road; More Work Ahead |page=1 |work=The Bellingham Herald |url=https://www.newspapers.com/clip/89610232/bellingham-freeway-in-use/ |via=Newspapers.com |access-date=November 26, 2021}}</ref> The remainder of I-5 from Ferndale to the Peace Arch border crossing was upgraded in two stages, beginning with {{convert|11|mi|km}} to Dakota Creek near Blaine that opened on October 29, 1963.<ref>{{cite news |date=October 29, 1963 |title=Rosellini Backs Parks Board In Dispute at Peace Arch |page=A |work=The Seattle Times}}</ref> The last section through Blaine was delayed by construction issues and opened on November 23, 1965, with a dedication ceremony at the Peace Arch.<ref>{{cite news |date=November 22, 1965 |title=Road to Beauty Opens Tuesday |page=7 |work=[[The Vancouver Sun]] |url=https://www.newspapers.com/clip/54941733/road-to-beauty-opens-tuesday/ |via=Newspapers.com |access-date=July 7, 2020}}</ref> The British Columbian government had already completed upgrades to its section of [[British Columbia Highway 99|Highway&nbsp;99]] between Blaine and the Fraser River in 1962.<ref>{{cite news |last=Deverell |first=Bill |date=May 30, 1962 |title=Brass of All Kinds on Hand For Opening of Deas Thruway |page=6 |work=The Sun |url=https://www.newspapers.com/clip/43699333/brass_of_all_kinds_on_hand_for_opening/ |via=Newspapers.com |access-date=July 7, 2020}}</ref> The southernmost section of the Bellingham Freeway through the Chuckanut Mountains opened in three stages in 1966, completing the last four-lane section of the highway in the state.<ref>{{cite web |date=November 3, 1966 |title=Official Opening: Bellingham Freeway |page=4 |publisher=Washington State Highway Commission |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll3/id/245 |via=WSDOT Library Digital Collections |access-date=July 7, 2020}}</ref><ref>{{cite news |date=November 3, 1966 |title=It's All Four-Lane Highway From Border to Border Now |page=1 |work=The Bellingham Herald |url=https://www.newspapers.com/clip/89610258/its-all-four-lane-highway-from-border/ |via=Newspapers.com |access-date=November 26, 2021}}</ref>

The {{convert|19.7|mi|km|adj=mid}} section between north Seattle and Everett was opened on February 3, 1965.<ref name="Enterprise-1965">{{cite news |date=February 3, 1965 |title=Seattle-Everett freeway opens today |page=1 |work=The Enterprise |location=Lynnwood, Washington}}</ref> It was constructed over sections of the former Seattle–Everett Interurban Railway and cost $23&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|23000000|1965}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}}<ref>{{cite news |last=Fish |first=Byron |date=September 4, 1964 |title=Everett Interurban Did a Freeway's Job |page=24 |work=The Seattle Times}}</ref> Several of the freeway's interchanges in southern Snohomish County were opened two months later.<ref>{{cite news |date=March 25, 1965 |title=3 Interchanges To Open Next Month |page=1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Barr |first=Robert A. |date=January 25, 1965 |title=Big Freeway Jams Expected Because of Uncompleted Exits |page=1 |work=The Seattle Times}}</ref> The freeway was initially six lanes wide but was expanded to eight lanes from Northgate to modern-day Shoreline in 1966 because of increased traffic congestion.<ref>{{cite news |last=Barr |first=Robert A. |date=November 10, 1966 |title=Reversible Traffic In Freeway To Be Diverted |page=1 |work=The Seattle Times}}</ref> The {{convert|3|mi|km|adj=mid}} bypass of downtown Everett between 41st Street and the Snohomish River was completed on January 18, 1968;<ref>{{cite news |last=Barr |first=Robert A. |date=January 18, 1968 |title=Everett Freeway Bypass Is Opened |page=45 |work=The Seattle Times}}</ref> its opening eliminated fourteen traffic lights and included ramps to connect with the Hewitt Avenue Trestle.<ref>{{cite news |date=January 16, 1968 |title=Freeway Set For Opening |page=A1 |work=The Everett Herald |url=https://www.newspapers.com/article/the-daily-herald-freeway-set-for-opening/140629028/ |via=Newspapers.com |accessdate=February 10, 2024}}</ref> The final section of I-5 was opened on May 14, 1969, spanning {{convert|3.5|mi|km}} between Everett and Marysville over the Snohomish River delta.<ref>{{cite news |last=Mansfield |first=Tom |date=May 14, 1969 |title=I-5 Opened Today |page=A1 |work=The Everett Herald |url=https://www.newspapers.com/article/the-daily-herald-i-5-opened-today/139874637/ |via=Newspapers.com |accessdate=February 10, 2024}}</ref><ref>{{cite book |last1=Cameron |first1=David A. |last2=LeWarne |first2=Charles P. |last3=May |first3=M. Allan |last4=O'Donnell |first4=Jack C. |last5=O'Donnell |first5=Lawrence E. |year=2005 |title=Snohomish County: An Illustrated History |pages=331–332 |publisher=Kelcema Books LLC |location=Index, Washington |isbn=978-0-9766700-0-1 |oclc=62728798}}</ref> It was originally scheduled to open several months earlier, but delayed steel work on the bridge over the Snohomish River caused scheduling issues.<ref>{{cite news |last=Barr |first=Robert A. |date=September 1, 1968 |title=Completion of Everett Link Delayed |page=1 |work=The Seattle Times}}</ref>

Several [[right-in/right-out]] intersections and non-grade-separated sections remained on I-5 until the completion of widening and grade separation projects in the 1970s.<ref>{{cite web |date=November 1972 |title=Project Status Report: Interstate 5, Cowlitz–Lewis County Line Vicinity to Koontz Road |publisher=Washington State Highway Commission |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll3/id/583/rec/6 |via=WSDOT Library Digital Collections |access-date=December 29, 2018}}</ref><ref>{{cite news |date=April 2, 1972 |title=Major interchange due to open north of Marysville |page=A19 |work=The Seattle Times}}</ref> The section between northern Kelso and Castle Rock was improved to Interstate standards and widened to six lanes in 1976,<ref>{{cite news |last=Vink |first=Graham |date=April 22, 1977 |title=I-5 expansion through Kelso outlined here |page=7 |work=The Daily News |url=https://www.newspapers.com/clip/77609886/i-5-expansion-through-kelso-outlined/ |via=Newspapers.com |access-date=May 12, 2021}}</ref> which was followed by an expansion through Kelso that opened in 1981.<ref>{{cite news |date=June 15, 1981 |title=New freeway lanes to open |page=A1 |work=The Daily News |url=https://www.newspapers.com/clip/77610068/new-freeway-lanes-to-open/ |via=Newspapers.com |access-date=May 12, 2021}}</ref><ref>{{cite news |date=November 1, 1978 |title=I-5 won't look good for a while |page=18 |work=The Daily News |url=https://www.newspapers.com/clip/77610102/i-5-wont-look-good-for-a-while/ |via=Newspapers.com |access-date=May 12, 2021}}</ref> The Kelso expansion project included relocating the freeway away from a mudslide-prone hill, transferring maintenance of the old alignment to the city government.<ref>{{cite news |last=Paulu |first=Tom |date=July 22, 1981 |title=Cost of Kelso's freeway 'gift' questioned |page=B1 |work=The Daily News |url=https://www.newspapers.com/clip/77610029/cost-of-kelsos-freeway-gift/ |via=Newspapers.com |access-date=May 12, 2021}}</ref> A similar six-lane expansion project in Marysville in the late 1960s was delayed after a dispute between the state government and [[Tulalip Tribes]] over compensation for land that was later settled in 1970.<ref>{{cite news |last=Barr |first=Robert A. |date=March 16, 1969 |title=Angry Indians Stall Paleface Path |page=39 |work=The Seattle Times}}</ref><ref>{{cite news |last=Barr |first=Robert A. |date=October 16, 1970 |title=Indians, state 'bury hatchet' over land |page=D5 |work=The Seattle Times}}</ref> A section further north of Marysville was expanded to six lanes in 1972, including a new bridge over the Stillaguamish River for northbound traffic and replacement of a railroad underpass with a pair of overpasses.<ref>{{cite news |last=Barr |first=Robert A. |date=July 16, 1972 |title=Rain stalls I-5 reconstruction project |page=H7 |work=The Seattle Times}}</ref><ref>{{cite news |last=Barr |first=Robert A. |date=June 30, 1970 |title=6-Lane Highway Being Relocated Over Rail Line |page=B2 |work=The Seattle Times}}</ref>

===Seattle planning and construction===
[[File:Seattle - Interstate 5 under construction, 1963 (46535962192).jpg|thumb|right|Land clearing for I-5 near [[Green Lake (Seattle)|Green Lake]] in north Seattle, pictured in 1963]]

A municipal traffic plan from 1946 outlined designs for a north–south freeway through Seattle that was later refined into the early concepts for Interstate 5 in the 1950s.<ref name="WANews-1962">{{cite news |date=June 1962 |title=The Seattle Freeway |pages=16–17 |work=Washington Highway News |publisher=Washington State Department of Highways |volume=9 |issue=12 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/4256/ |via=WSDOT Library Digital Collections |access-date=September 24, 2018}}</ref> A design from 1954 proposed an eight-lane facility from Downtown Seattle to [[Ravenna, Seattle|Ravenna]] that would cost $194&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|194000000|1954}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} to construct.<ref>{{cite news |date=December 31, 1957 |title=Schedule For Freeway Up To Congress |page=3 |work=The Seattle Times}}</ref> Alternate plans would have placed the freeway further east on 12th Avenue in Capitol Hill or along [[Empire Way (Seattle)|Empire Way]], which would later be used for the proposed [[R. H. Thomson Expressway]].<ref>{{cite news |last=Cunningham |first=Ross |date=February 5, 1957 |title=House Group to Hold Hearing on Proposal To Shift Freeway |page=6 |work=The Seattle Times}}</ref> A larger, twelve-lane freeway through Downtown Seattle with a reversible express lane system was announced in April 1957 ahead of a series of [[public hearing]]s.<ref>{{cite news |date=April 21, 1957 |title=Route for Proposed Freeway Announced for Public Hearing |page=16 |work=The Seattle Times}}</ref> The proposal received a mix of strong support and criticism from members of the public, while the city government endorsed the plan with a caveat that [[Right-of-way (property access)|right of way]] along the freeway be reserved for use by [[rapid transit]].<ref>{{cite news |date=April 26, 1957 |title=Officials Study Reactions To Freeway Plan |page=25 |work=The Seattle Times}}</ref><ref>{{cite news |date=August 21, 1957 |title=State Won't Share Cost Of Seattle-Area Traffic Survey |page=15 |work=The Seattle Times |agency=Associated Press}}</ref> The twelve-lane design, sans transit, was approved the following year by the Bureau of Public Roads, allowing for property acquisition to begin.<ref>{{cite news |date=January 31, 1958 |title=Approval Obtained For Twelve Lane Design |page=1 |work=Seattle Freeway News |publisher=Washington State Highway Commission |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll11/id/2134/rec/3 |via=WSDOT Digital Library Collections |access-date=August 6, 2018}}</ref><ref>{{cite news |date=January 12, 1958 |title=O. K. on 12 Lanes to Speed Freeway Job, Says Bugge |page=7 |work=The Seattle Times}}</ref><ref>{{cite news |last=Hill |first=Gene |date=January 5, 1958 |title=Much Property for Freeway Right of Way Has Been Purchased by State |page=21 |work=The Seattle Times}}</ref> A dedicated office was created to handle property acquisition, which would require 4,500 [[Land lot|parcel]]s of land, and 10 percent were condemned by the government.<ref>{{cite web |last=Becker |first=Paula |date=December 1, 2002 |title=Washington establishes an office for clearing the route of the Seattle Freeway (Interstate 5) on April 1, 1957. |url=http://www.historylink.org/File/4168 |work=HistoryLink |access-date=December 28, 2018}}</ref><ref>{{cite news |date=February 20, 1958 |title=Appraisal, Purchase of 1,000 More Tracts for Freeway Begins |page=12 |work=The Seattle Times}}</ref>

The first section of the freeway within Seattle to be built was the [[Ship Canal Bridge]], a double-decker bridge over the [[Lake Washington Ship Canal]] between the [[University District, Seattle|University District]] and [[Eastlake, Seattle|Eastlake]], which began construction in August 1958.<ref>{{cite news |date=August 21, 1958 |title=Next Steps For Freeway Outlined |page=45 |work=The Seattle Times}}</ref> Construction of the freeway through Downtown Seattle was delayed after 100 citizens marched on June 1, 1961, in protest of the "trench" design and sought to add a lidded tunnel with a rooftop park.<ref>{{cite news |last=Duncan |first=Don |date=June 1, 1961 |title=100 Marchers Call For Freeway Lid |page=1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Lane |first=Bob |date=December 14, 1961 |title='Lid' Dispute Stalls Freeway Work 5 Months |page=1 |work=The Seattle Times}}</ref> The proposed design change was deferred for later consideration, but delayed the start of construction south of Olive Way to the following year.<ref>{{cite news |last=Harvey |first=Barney |date=July 2, 1962 |title=Confusion: That's Name For Freeway |page=1 |work=The Seattle Times}}</ref>

Land acquisition for the downtown section of I-5 was completed in June 1962 after a series of condemnations were settled by the [[King County Superior Court]].<ref>{{cite news |date=June 13, 1962 |title=All Downtown Freeway Area Now Acquired |page=10 |work=The Seattle Times}}</ref> Demolition of buildings along the block-wide right-of-way had already begun, including the [[Kalmar Hotel]] (built in 1881), which pre-dated the [[Great Seattle Fire]],<ref>{{cite news |date=April 12, 1962 |title=Wreckers Begin To Raze Kalmar Hotel |page=4 |work=The Seattle Times}}</ref> and the Seventh Avenue Fire Hall (built in 1890), the oldest public building in the city.<ref name="HL-FirstHill">{{cite web |last=Becker |first=Paula |date=April 30, 2003 |title=First Hill neighborhood objects to the Seattle Freeway route at a public hearing on September 13, 1961. |url=https://www.historylink.org/File/4167 |work=HistoryLink |access-date=November 7, 2007}}</ref><ref>{{cite book |last=Steinbrueck |first=Victor |author-link=Victor Steinbrueck |year=1962 |title=Seattle Cityscape |page=43 |publisher=[[University of Washington Press]] |oclc=2098110}}</ref> The demolitions were opposed by local preservationists, among them architects [[Victor Steinbrueck]] and [[Paul Thiry (architect)|Paul Thiry]], but proceeded as planned.<ref name="HL-FirstHill"/> Thiry described the freeway's construction as when "Seattle began taking one of its wrong turns and started to lose its identity as a city" and proposed a park lid from Columbia Street to Olive Way along the entire downtown section of I-5.<ref>{{cite book |last=Jones |first=Nard |year=1972 |title=Seattle |page=21 |publisher=[[Doubleday (publisher)|Doubleday]] |isbn=0-385-01875-4 |oclc=532396}}</ref> Seattle's Chinatown was divided by the construction of I-5, which resulted in the formation of a special district to preserve the neighborhood's Asian American heritage.<ref>{{cite web |date=June 5, 2018 |title=Seattle Chinatown Historic District |url=https://www.nps.gov/places/seattle-chinatown-historic-district.htm |publisher=[[National Park Service]] |accessdate=May 9, 2023}}</ref>

The Ship Canal Bridge and {{convert|2.2|mi|km}} of freeway between Ravenna Boulevard and Roanoke Street were dedicated and opened to traffic on December 18, 1962. The bridge cost $14&nbsp;million to construct (equivalent to ${{Format price|{{Inflation|US-GDP|14000000|1962}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} and was among the largest ever built in the Pacific Northwest.<ref>{{cite news |date=December 12, 1962 |title=Traffic on Freeway: Span-Opening Ceremony Due |page=2 |work=The Seattle Times}}</ref><ref>{{cite news |date=December 19, 1962 |title=Freeway Ribbon Cut: Rehearsal Becomes Real Thing |page=22 |work=The Seattle Times}}</ref> After the opening of the [[Evergreen Point Floating Bridge (1963)|Evergreen Point Floating Bridge]] on August 28, 1963, traffic from the bridge was permitted to use a section of I-5 between SR&nbsp;520 and Mercer Street.<ref>{{cite news |date=August 30, 1963 |title=To Mercer Exit Freeway Users Soon can Go |page=1 |work=The Seattle Times}}</ref> Traffic from the North Seattle section, which had been extended north from Ravenna Boulevard to [[Washington State Route 522|Bothell Way]] (SR&nbsp;522), was diverted until a through connection was opened on November 12.<ref>{{cite news |date=November 12, 1963 |title=Mercer Street: Freeway Access Almost Ready |page=12 |work=The Seattle Times}}</ref> The section in the Ravenna neighborhood also included a 300-person [[fallout shelter]] under the freeway at Weedin Place that was completed in 1963 and later used for records storage before its abandonment.<ref>{{cite web |last=Becker |first=Paula |date=August 9, 2010 |title=State of Washington breaks ground for a fallout shelter under the Seattle Freeway (Interstate 5) in Seattle's Ravenna neighborhood on May 15, 1962. |url=https://www.historylink.org/File/3705 |work=HistoryLink |access-date=July 7, 2020}}</ref> Some sections of the extensive [[retaining walls]] along I-5 were pre-assembled at a plant in [[Woodinville, Washington|Woodinville]] and hoisted in place by a crane to reduce working hours in residential neighborhoods.<ref>{{cite news |last=Barr |first=Robert A. |date=October 2, 1963 |title=Freeway 'Assembly Line': Huge Walls Go Up in a Hurry |page=36 |work=The Seattle Times}}</ref>

[[File:Aerial of Interstate 5, north from Downtown Seattle, 1971.jpg|thumb|left|The completed downtown section of I-5, looking north from University Street in 1971, before the construction of [[Freeway Park]] and the [[Seattle Convention Center]]]]

The remaining downtown section and approaches from the suburbs remained scheduled to be completed by 1967, with the state legislature passing a provision in a spending bill to accelerate construction.<ref>{{cite news |last=Burt |first=Lyle |date=January 20, 1963 |title=State Plans to Open Freeway Stretch Soon |page=22 |work=The Seattle Times}}</ref><ref>{{cite news |date=April 19, 1963 |title=Rosellini Signs Highway Measure |page=37 |agency=Associated Press |work=The Seattle Times}}</ref> The delayed timeline was blamed by the Department of Highways on several uncontrollable factors, among them landslides along Beacon Hill and Capitol Hill, unfavorable weather, a cement masons strike, and relocation of utilities.<ref>{{cite news |last=Barr |first=Robert A. |date=June 12, 1966 |title=Strike, Slides May Delay Freeway Date |page=4 |work=The Seattle Times}}</ref><ref>{{cite news |date=October 19, 1966 |title=Opening Of Freeway Units Postponed |page=12 |work=The Seattle Times}}</ref> The section between Olive Way and Mercer Street opened to limited traffic on October 30, 1964, with two northbound lanes to bypass congestion at the Mercer Street interchange.<ref>{{cite news |date=October 28, 1964 |title=Olive-Mercer Link Of Freeway to Open |page=1 |work=The Seattle Times}}</ref> Two additional downtown interchanges at University Street and Cherry Street opened on June 30, 1966.<ref>{{cite news |last=Barr |first=Robert A. |date=July 1, 1966 |title=Freeway Habit Hard to Break: 2 New On-Ramps 'Ignored' |page=1 |work=The Seattle Times}}</ref> Access to the northbound lanes of I-5 was extended to South Dearborn Street in late September 1966, while opening of the southbound section was delayed because of issues with the Airport Way exit.<ref>{{cite news |last=Barr |first=Robert A. |date=September 25, 1966 |title=Northbound Freeway Unit to Open Thursday |page=55 |work=The Seattle Times}}</ref> The Connecticut Street interchange, intended to be part of I-90 and connected to the Alaskan Way Viaduct, was partially constructed as part of the downtown section of I-5 but was left unfinished until 1991.<ref>{{cite news |date=September 15, 1966 |title=Freeway Complex Readied South of Downtown |page=59 |work=The Seattle Times}}</ref><ref name="PI-Ramps1991">{{cite news |date=November 18, 1991 |title='Ramps to nowhere' open today |page=B1 |work=Seattle Post-Intelligencer}}</ref> The remainder of the Seattle section, a {{convert|17.2|mi|km|adj=mid}} stretch from Midway to Olive Way, was opened to traffic on January 31, 1967, by Governor [[Daniel J. Evans|Dan Evans]].<ref name="Times-1967Final">{{cite news |last=Heilman |first=Robert |date=January 31, 1967 |title=Ceremony Opens Final Freeway Link |page=1 |work=The Seattle Times}}</ref>

The reversible express lane system was built along with the rest of I-5 through Seattle and opened in separate phases. The first section of reversible lanes opened on June 2, 1965, with 13 access ramps between Olive Way and Northgate Mall.<ref>{{cite news |last=Barr |first=Robert A. |date=June 3, 1965 |title=New Reversible Route Relieves Traffic Congestion on Freeway |page=21 |work=The Seattle Times}}</ref><ref>{{cite news |date=May 3, 1965 |title=Reversible Lanes to Aid Traffic Flow |page=13 |work=The Seattle Times}}</ref> The express lanes were managed using a series of ramp barriers that were remotely controlled and monitored by eleven [[closed-circuit television]] cameras that were activated in September 1965.<ref>{{cite news |last=Barr |first=Robert A. |date=May 13, 1964 |title=State Highway engineers Explain Reversible-Expressway System |page=10 |work=The Seattle Times}}</ref><ref>{{cite news |last=Barr |first=Robert A. |date=September 13, 1965 |title=Closed-Circuit TV Soon Will Control Freeway Lanes |page=4 |work=The Seattle Times}}</ref> An additional ramp at the Mercer Street interchange opened in October 1966 after southbound traffic was diverted to a new set of ramps.<ref>{{cite news |last=Barr |first=Robert A. |date=October 18, 1966 |title=Mercer St. Reversible Exit to Open Tuesday |page=1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Barr |first=Robert A. |date=October 27, 1966 |title=Freeway Jam Eased by New Lanes |page=1 |work=The Seattle Times}}</ref> The southernmost section of the express lanes, including ramps to Columbia and Cherry streets at 5th Avenue, opened on January 31, 1967.<ref name="Times-1967Final"/> The new ramps were later converted to [[bus lane|bus-only]] use as part of the [[Route 41 (King County Metro)|Blue Streak]] express bus program, which debuted in 1970 and was later replaced by a [[King County Metro]] route.<ref>{{cite news |last=Lane |first=Bob |date=August 30, 1970 |title=September 9: Blue Streak buses roll soon |page=A11 |work=The Seattle Times}}</ref><ref>{{cite news |last=Lane |first=Bob |date=January 18, 1978 |title=Signs of change for Metro buses |page=E12 |work=The Seattle Times}}</ref>

===Major projects and expansions===
[[File:Aerial view of Freeway Park at night, looking south from Pine and 9th.jpg|thumb|right|Aerial view of [[Freeway Park]], looking south]]

The First Hill Improvement Club and architect Paul Thiry led a campaign in 1961 to reconnect areas of Seattle severed by the freeway with lids that would house parks, [[parking garage]]s, and other buildings through leased [[air rights]].<ref>{{cite news |date=April 30, 1961 |title=Questions and Answers on Rival Freeway Plans—Open or Covered? |page=12 |work=The Seattle Times}}</ref><ref>{{cite news |last=Jacobi |first=Wayne |date=September 28, 1961 |title=Lease On Freeway Air Space Sought |page=1 |work=The Seattle Times}}</ref> The lid proposal was approved in October 1969 with funding split between the local government, state government, the [[Forward Thrust]] bonds program, and a private developer.<ref>{{cite news |date=October 17, 1969 |title=Freeway Park Approved |page=14 |work=The Seattle Times}}</ref> Landscape architects [[Lawrence Halprin]] and [[Angela Danadjieva]] were selected to design the park lid and adjoining parking garages, which would incorporate [[Brutalist architecture|Brutalist]] elements and a series of [[waterfall]]s.<ref>{{cite news |last=Lane |first=Polly |date=November 22, 1970 |title=Freeway lid: Halprin to do park project |page=C1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Lane |first=Polly |date=June 22, 1975 |title=Designer pleased by progress |page=D6 |work=The Seattle Times}}</ref>

The {{convert|5.5|acre|ha|adj=mid}} [[Freeway Park]] opened on July 4, 1976, incorporating pedestrian and open spaces between Seneca and University streets that continued up the northwest slope of First Hill.<ref name="TCLF">{{cite web |date=October 10, 2006 |title=Freeway Park: Past, Present, and Future? |url=https://tclf.org/content/freeway-park-past-present-and-future |publisher=[[The Cultural Landscape Foundation]] |access-date=July 8, 2020}}</ref><ref>{{cite news |date=April 8, 1973 |title=Freeway Park design OK'd |page=E1 |work=The Seattle Times}}</ref> The [[Washington State Convention Center|Washington State Convention and Trade Center]] (now the Seattle Convention Center) was constructed north of Freeway Park over a section of I-5 and opened in 1988.<ref name="HL-FirstHill"/><ref>{{cite news |last=Lane |first=Polly |date=March 27, 1984 |title=Convention site official; freeway lid wins |page=C3 |work=The Seattle Times}}</ref> Part of the convention center complex was designed by Danadjieva as a continuation of Freeway Park, while the main structure rested on a series of trusses over I-5.<ref>{{cite news |last=Boss |first=Kit |date=June 10, 1988 |title=Unconventional look: Convention center draws favorable reviews with its textured fascade, mix of plantings, glass, concrete |page=D1 |work=The Seattle Times}}</ref> In 2019, the Seattle city government approved funding for a feasibility study for an expanded downtown lid after lobbying from a [[grassroots]] campaign.<ref>{{cite news |last=Baume |first=Matt |date=January 13, 2016 |title=The Big Lid |url=https://www.thestranger.com/features/feature/2016/01/13/23410742/the-big-lid |work=The Stranger |access-date=July 8, 2020}}</ref><ref>{{cite news |last=Conroy |first=Bill |date=May 2019 |title=The Drive to Close Downtown Seattle's Freeway Divide Gains Speed |pages=18–20 |url=https://www.seattlebusinessmag.com/real-estate/drive-close-downtown-seattles-freeway-divide-gains-speed |work=Seattle Business Magazine |access-date=May 15, 2019 |archive-date=November 9, 2019 |archive-url=https://web.archive.org/web/20191109170737/http://www.seattlebusinessmag.com/real-estate/drive-close-downtown-seattles-freeway-divide-gains-speed |url-status=dead }}</ref> The [[I-5 Colonnade]], a {{convert|7.5|acre|m2|adj=on}} [[mountain bike]] park, opened in 2007 under an elevated section of the freeway between Eastlake and Capitol Hill.<ref>{{cite news |last=Johnston |first=Greg |date=March 29, 2007 |title=Mountain-bike club reclaims a wasteland |page=10 |url=http://seattlepi.nwsource.com/getaways/309155_colonnade29.html |work=Seattle Post-Intelligencer |archive-url=https://web.archive.org/web/20080115103626/http://seattlepi.nwsource.com/getaways/309155_colonnade29.html |archive-date=January 15, 2008 |access-date=November 7, 2007}}</ref>

WSDOT began installing [[ramp meter]]s in 1981 to address worsening onramp congestion on I-5 from Seattle to Mountlake Terrace. The first set of 16 ramp meters were activated on September 30, 1981, with a computer system controlling entry at 5–15 second increments; some ramps also had un-metered bypass lanes for transit and three-person [[carpooling|carpools]].<ref>{{cite news |last=Norton |first=Dee |date=September 29, 1981 |title=Freeway computer to debut tomorrow |page=B1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Duncan |first=Don |date=October 4, 1981 |title=FLOW: Control-center crew stayed calm |page=D2 |work=The Seattle Times}}</ref> The state's first set of [[high-occupancy vehicle lane|HOV lanes]] opened in August 1983 for use by buses and carpools from Northgate to Mountlake Terrace.<ref>{{cite news |date=August 25, 1983 |title=Bus/carpool lanes, opening Monday, to improve traffic on I-5 north of city |page=D27 |work=The Seattle Times}}</ref> By the late 1980s, the {{convert|36|mi|km}} of HOV lanes had reduced average travel times on I-5 by four minutes despite an 86 percent increase in traffic volumes.<ref>{{cite news |last=Dickie |first=Lance |date=May 21, 1989 |title=Can commuters love HOVs? |page=A19 |work=The Seattle Times}}</ref> The HOV lanes were extended north to Lynnwood in 1996 and southern Everett by the end of the decade, while the carpool minimum was lowered to two people per vehicle.<ref>{{cite news |last=Penhale |first=Ed |date=June 15, 1995 |title=Freeway car-pool lanes might return to three-person minimum |page=A1 |work=Seattle Post-Intelligencer}}</ref><ref>{{cite news |last=Gilmore |first=Susan |date=May 25, 2002 |title=More to HOV options than opening lanes |page=B1 |work=The Seattle Times}}</ref>

In the 1970s, the state government began planning extensive rebuilding of the oldest sections of I-5 to meet newer Interstate standards and eliminate design issues.<ref>{{cite news |last=Bacon |first=Leonard |date=November 28, 1972 |title=Vancouver council to hear public views of new I-5 route |page=10 |work=The Oregonian}}</ref> The {{convert|6.5|mi|km|adj=mid}}, four-lane section through Tumwater, Olympia, and Lacey was rebuilt in the 1980s at a cost of $164&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|164000000|1991}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}} The freeway project was completed in late 1991 with an expansion to six lanes, six rebuilt interchanges, a new bridge for Capitol Way, and improved landscaping.<ref>{{cite news |last=Oakland |first=Mike |date=November 15, 1991 |title=I-5: 'Finally over'; 8 years later, the work is done |page=C1 |work=The Olympian |url=https://www.newspapers.com/clip/97791235/i-5-finally-over-8-years-later-the/ |via=Newspapers.com |access-date=March 17, 2022}}</ref><ref>{{cite news |last=Gough |first=William |date=February 8, 1987 |title=Olympia traffic mess to end—eventually |page=B2 |work=The Seattle Times}}</ref> The existing Pacific Avenue interchange near the Tacoma Dome was expanded in the 1980s to accommodate [[Interstate 705|I-705]], a new spur freeway traveling north to downtown Tacoma.<ref>{{cite news |last=Bailey |first=Gil |date=October 14, 1988 |title=Tacoma is big on new little freeway |page=C2 |work=Seattle Post-Intelligencer}}</ref>

The rebuilding of the {{convert|3|mi|km|adj=mid|spell=in}} Vancouver section was completed in August 1983 at a cost of $40&nbsp;million (equivalent to ${{Format price|{{Inflation|US-GDP|40000000|1983}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}} It included widening the freeway to six lanes, new interchanges with SR&nbsp;14 and SR&nbsp;500, relocation of railroad tracks, and the replacement of several overpasses.<ref>{{cite news |last=Hamilton |first=Don |date=March 7, 1983 |title=Final highway touches eyed |page=B7 |work=The Oregonian}}</ref><ref>{{cite news |last=Richards |first=Leverett |date=July 19, 1983 |title=New links to Interstate Bridge to open soon |page=M4 |work=The Oregonian}}</ref> An additional expansion project on I-5 through Vancouver and Hazel Dell was completed in 2001, replacing the original overpasses and adding a southbound HOV lane.<ref>{{cite news |last=Ryll |first=Thomas |date=October 28, 2001 |title=Finally, an all-new freeway |page=A1 |work=The Columbian}}</ref><ref>{{cite news |last=Painter |first=John Jr. |date=October 30, 2001 |title=HOV lane opens, cuts traffic time on south I-5 |page=B1 |work=The Oregonian}}</ref> The HOV lane was later removed in 2005 after drivers complained about increased travel times for single-occupant vehicles.<ref>{{cite news |last=Jenkins |first=Don |date=August 10, 2005 |title=Drivers jeer, cheer end of HOV lane |page=A1 |work=The Columbian}}</ref> A second widening project, completed in 2006, added two lanes on a from Hazel Dell to the I-205 interchange in Salmon Creek, where a new ramp to Northeast 139th Street was later opened in 2014.<ref>{{cite news |last=Ryll |first=Thomas |date=July 12, 2006 |title=Ahead of schedule |page=A1 |work=The Columbian}}</ref><ref>{{cite news |last=Florip |first=Eric |date=August 28, 2014 |title=Leaders celebrate completion of Salmon Creek project |page=C1 |url=https://www.columbian.com/news/2014/aug/27/leaders-celebration-completion-salmon-creek-interc/ |work=The Columbian |access-date=July 13, 2020}}</ref>

[[File:I-5 southbound from 75th Street in Everett (18345043233).jpg|thumb|left|An expanded section of I-5 in [[Everett, Washington|Everett]], featuring HOV lanes and sound walls]]

In April 2003, the state legislature passed the [[Nickel Project|Nickel Funding Package]], which enacted a five-cent gas tax increase to fund $4.2&nbsp;billion in transportation projects (equivalent to ${{Format price|{{Inflation|US-GDP|4200000000|2003}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} that were rejected in an earlier public [[referendum]].<ref>{{cite news |author=Phuong Cat Le |date=April 27, 2003 |title=Legislature 2003: Help for roads and ferries |page=B1 |url=https://www.seattlepi.com/news/article/Legislature-2003-Help-for-roads-and-ferries-1113390.php |work=Seattle Post-Intelligencer |access-date=July 13, 2020}}</ref> The program funded several projects to widen and modernize sections of I-5, including new interchanges in Clark County and the extension of HOV lanes in Everett and from Tukwila to Tacoma.<ref>{{cite web |date=September 13, 2005 |title="Nickel Funding Package" Enacted for Transportation by the 2003 Washington State Legislature |url=http://www.wsdot.wa.gov/NR/rdonlyres/A5AA153E-8928-412C-809E-EBE24DE88662/0/HighwayNickelList.pdf |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20070104015832/http://www.wsdot.wa.gov/NR/rdonlyres/A5AA153E-8928-412C-809E-EBE24DE88662/0/HighwayNickelList.pdf |archive-date=January 4, 2007 |access-date=July 13, 2020}}</ref> Several direct access ramps for the HOV lanes were constructed in the 2000s using funds from [[Sound Transit]] to serve bus facilities in Lynnwood and Federal Way.<ref>{{cite news |last=Brown |first=Charles E. |date=July 31, 2006 |title=Bumper to Bumper: Why access ramps in the middle of I-90? |page=B1 |work=The Seattle Times}}</ref><ref>{{cite news |last=Maynard |first=Steve |date=February 6, 2006 |title=Federal Way transit hub here at last |page=B1 |work=The News Tribune |location=Tacoma, Washington}}</ref> The Everett expansion project cost $263&nbsp;million to construct and consisted of HOV lanes from the Everett Mall to the Snohomish River, realigned ramps, a new single-point urban interchange at 41st Street, and a reconstructed Broadway interchange with HOV ramps and a flyover ramp. Construction began in September 2005 under a [[design–build]] contract, the third in WSDOT's history, and was completed in June 2008 as part of an accelerated timeline to prepare for the [[2010 Winter Olympics]] hosted by Vancouver, British Columbia.<ref>{{cite news |last=Nohara |first=Yoshiaki |date=March 4, 2008 |title=Headache looming on I-5 in Everett |url=https://www.heraldnet.com/news/headache-looming-on-i-5-in-everett/ |work=The Everett Herald |access-date=July 13, 2020}}</ref><ref>{{cite press release |date=June 5, 2008 |title=Crossing the finish line on I-5 in Everett |url=http://www.wsdot.wa.gov/News/2008/05/5_NewEverettHOVRamps.htm |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20080804123830/http://www.wsdot.wa.gov/News/2008/05/5_NewEverettHOVRamps.htm |archive-date=August 4, 2008 |access-date=July 13, 2020}}</ref>

The southern end of the HOV lanes on I-5 in King County was extended to SR&nbsp;516 in 1995 and Federal Way in 2007 using Nickel Package funding.<ref>{{cite web |title=I-5 HOV Lanes, Pierce County Line to Tukwila: Project Phases |url=http://www.wsdot.wa.gov/Projects/I5/hovPiercetoTukwila/phases |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20080513181316/http://www.wsdot.wa.gov/Projects/I5/hovPiercetoTukwila/phases |archive-date=May 13, 2008 |access-date=July 13, 2020}}</ref> Construction of an HOV lane system through Tacoma, which would also include a new interchange with SR&nbsp;16 and the Nalley Valley Viaduct, began in 2001 with the replacement of the South 38th Street overpass to accommodate a wider freeway.<ref>{{cite news |last=Corvin |first=Aaron |date=July 23, 2001 |title=HOV lanes heading this way |page=B1 |work=The News Tribune |location=Tacoma, Washington}}</ref><ref>{{cite news |last1=Corvin |first1=Aaron |last2=Vedder |first2=Mina |date=July 30, 2001 |title=Don't fret, 38th Street overpass is past halfway |page=A1 |work=The News Tribune |location=Tacoma, Washington}}</ref> The Tacoma/Pierce County HOV program launched with partial funding for the $1.6&nbsp;billion [[megaproject]] that was later filled with an [[earmark (politics)|earmark]] in the state legislature's 2005 transportation funding package.<ref name="KUOW-Tacoma">{{cite news |last=Boiko-Weyrauch |date=March 28, 2018 |title=Traffic at this spot on I-5 has been terrible for 25 years. Here's why |url=http://archive.kuow.org/post/traffic-spot-i-5-has-been-terrible-25-years-heres-why |publisher=KUOW |access-date=July 13, 2020}}</ref><ref>{{cite news |last=Lynn |first=Adam |date=April 26, 2005 |title=Car pools win gas tax gold |page=A1 |url=http://www.thenewstribune.com/news/local/story/4808300p-4422595c.html |work=The News Tribune |location=Tacoma, Washington |archive-url=https://web.archive.org/web/20051218013355/http://www.thenewstribune.com/news/local/story/4808300p-4422595c.html |archive-date=December 18, 2005 |access-date=July 13, 2020}}</ref> Construction on the HOV lanes began in 2009 with an extension through Fife to Port of Tacoma Road and [[seismic retrofit]]ting of bridges that was completed two years later.<ref>{{cite news |last=Henrikson |first=John |date=February 21, 2011 |title=Massive I-5 overhaul is under way |page=A3 |work=The News Tribune |location=Tacoma, Washington}}</ref><ref>{{cite news |last=McCarthy |first=Jane |date=August 14, 2009 |title=I-5 HOV project begins in Fife |url=http://www.nwcn.com/topstories/stories/NW_081409WAB-pierce-county-hov-lanes-LJ.dc4bf48c.html |publisher=[[Northwest Cable News]] |archive-url=https://web.archive.org/web/20090817125514/http://www.nwcn.com/topstories/stories/NW_081409WAB-pierce-county-hov-lanes-LJ.dc4bf48c.html |archive-date=August 17, 2009 |access-date=July 13, 2020}}</ref> The reconstructed SR&nbsp;16 opened in two phases, with the new westbound viaduct carrying all between its opening in June 2011 and the completion of the eastbound viaduct in August 2014.<ref>{{cite news |last=Carson |first=Rob |date=August 16, 2014 |title=Sprague ramps ready to merge onto I-5 |page=A1 |url=https://www.thenewstribune.com/news/local/traffic/article25876450.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref> A set of ramps connecting the HOV lanes of I-5 and SR&nbsp;16 on the Nalley Valley Viaduct opened in November 2019.<ref>{{cite press release |date=November 4, 2019 |title=I-5 and SR 16 HOV connections opening soon in Tacoma |url=https://wsdot.com/news/2019/11/04/i-5-and-sr-16-hov-connections-opening-soon-tacoma |publisher=Washington State Department of Transportation |access-date=July 13, 2020}}</ref>

WSDOT broke ground on the longest section of the Tacoma HOV program, spanning {{convert|4|mi|km}} from SR&nbsp;16 to Port of Tacoma Road, in July 2014.<ref>{{cite news |last=Carson |first=Rob |date=August 10, 2014 |title=Six-year overhaul of I-5 in Tacoma about to start |page=A1 |url=https://www.thenewstribune.com/news/local/traffic/article25875142.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref> The reconstructed section was completed in November 2018 with a new set of collector–distributor lanes,<ref>{{cite news |last=Lynn |first=Adam |date=April 8, 2017 |title=Exiting I-5 in Tacoma gets trickier later this month |page=A3 |url=https://www.thenewstribune.com/news/local/traffic/article143248719.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref> a carriageway for the northbound lanes of I-5 through the I-705 interchange, the replacement of two overpasses, and extended [[retaining wall]]s for excavated areas.<ref>{{cite web |title=I-5 - M Street to Portland Avenue - HOV - Complete November 2018 |url=https://www.wsdot.wa.gov/Projects/I5/MStToPortland/default.htm |publisher=Washington State Department of Transportation |access-date=July 13, 2020 |archive-date=July 16, 2020 |archive-url=https://web.archive.org/web/20200716114156/https://www.wsdot.wa.gov/Projects/I5/MStToPortland/default.htm |url-status=dead }}</ref><ref name="TNT-Slog">{{cite news |last=Carson |first=Rob |date=May 18, 2015 |title=No quick relief from the slog I-5 has become in Tacoma |page=A1 |url=https://www.thenewstribune.com/news/local/traffic/article26289529.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref> WSDOT began the final phase of the project, replacement of the Puyallup River crossing with wider bridges on a straighter alignment, in February 2015.<ref>{{cite press release |date=February 18, 2015 |title=Leaders celebrate construction start of new I-5 HOV project |url=http://www.wsdot.wa.gov/News/2015/02/NewHOVproject.htm |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20150316144254/http://www.wsdot.wa.gov/News/2015/02/NewHOVproject.htm |archive-date=March 16, 2015 |access-date=July 13, 2020}}</ref><ref>{{cite news |last=Nunnally |first=Derrick |date=September 4, 2015 |title=I-5 construction projects are moving along in Tacoma — but have years to go |page=A1 |url=https://www.thenewstribune.com/news/local/traffic/article33849396.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref> The {{convert|1,569|ft|m|adj=mid}} northbound bridge was completed in October 2017 and all traffic was shifted to it beginning in June 2019.<ref>{{cite news |last=Hill |first=Craig |date=October 27, 2017 |title=The new I-5 Puyallup River Bridge is about to open. But first, more closures |page=A4 |url=https://www.thenewstribune.com/news/local/article181128191.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref><ref>{{cite news |last=Sailor |first=Craig |date=June 7, 2019 |title=Lanes to shift on I-5 in Tacoma again as work on new bridge over Puyallup River begins |page=A4 |url=https://www.thenewstribune.com/news/local/article231256158.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref> The southbound bridge was opened to traffic in April 2022 and the HOV lanes were fully opened from Fife to SR&nbsp;16 in late August.<ref>{{cite news |date=April 1, 2022 |title=Relief at last? New Interstate 5 Puyallup River bridge has opened in Tacoma |url=https://www.thenewstribune.com/news/local/article260014465.html |work=The News Tribune |access-date=April 1, 2022}}</ref><ref>{{cite news |last=Sailor |first=Craig |date=August 27, 2022 |title=After two decades of construction it's finally here: Tacoma's I-5 HOV project opens Friday |url=https://www.thenewstribune.com/news/local/traffic/article262975678.html |work=The News Tribune |access-date=November 23, 2022}}</ref>

The 2003 and 2005 gas tax programs also funded improvements to I-5 in areas outside of the central Puget Sound region, including $322&nbsp;million for lane expansions on a {{convert|18|mi|km|adj=mid}} corridor in Lewis and Thurston counties.<ref name="WSDOT-Centralia16">{{cite press release |date=August 24, 2016 |title=Safety and congestion-relief work wraps up on I-5 in south Thurston and north Lewis counties |url=http://www.wsdot.wa.gov/news/2016/08/24/safety-and-congestion-relief-work-wraps-i-5-south-thurston-and-north-lewis-counties |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20160828214219/http://www.wsdot.wa.gov/news/2016/08/24/safety-and-congestion-relief-work-wraps-i-5-south-thurston-and-north-lewis-counties |archive-date=August 28, 2016 |access-date=July 14, 2020}}</ref><ref>{{cite news |last=Schwartz |first=Eric |date=April 2, 2008 |title=I-5 on the Verge of Major Change |url=http://www.chronline.com/news/i-5-on-the-verge-of-major-change/article_7d521d2f-5e53-5e78-b4bd-e170616e27ed.html |work=The Daily Chronicle |location=Centralia, Washington |access-date=July 14, 2020}}</ref> The existing four-lane section from US&nbsp;12 in Grand Mound to SR&nbsp;121 in Maytown gained a third lane in each direction that opened in November 2010 at a cost of $61.5&nbsp;million.<ref>{{cite press release |date=November 18, 2010 |title=New lane opens on northbound I-5 in Thurston County |url=http://www.wsdot.wa.gov/News/2010/11/18_NewLaneOpensNBI5_.htm |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20110126222051/http://www.wsdot.wa.gov/News/2010/11/18_NewLaneOpensNBI5_.htm |archive-date=January 26, 2011 |access-date=July 14, 2020}}</ref> The following year, the six-lane section was extended south by {{convert|4|mi|km|spell=in}} to Blakeslee Junction near Centralia. Widening of the {{convert|8|mi|km|adj=mid|spell=in}} section through Centralia to six lanes was completed in 2016 and also included the addition of collector–distributor lanes, three reconstructed interchanges, and flood control measures.<ref name="WSDOT-Centralia16"/><ref>{{cite news |last=Hughes |first=Lee |date=November 11, 2011 |title=I-5: A Whirl of Changes |url=http://www.chronline.com/news/local/i-5-a-whirl-of-changes/article_5814e6b6-0cf7-11e1-9e4f-001cc4c03286.html |work=The Daily Chronicle |location=Centralia, Washington |access-date=July 14, 2020}}</ref> A {{convert|20|mi|km|adj=mid}} section of the freeway from Chehalis to Grand Mound had closed for four days during [[Great Coastal Gale of 2007|December 2007 floods]] that covered the roadway in {{convert|10|ft|m}} of water from the Chehalis River.<ref>{{cite news |last1=Bernton |first1=Hal |last2=Thomas |first2=Ralph |date=December 5, 2007 |title=Flood-damaged I-5 to stay closed until this weekend |url=https://archive.seattletimes.com/archive/?date=20071205&slug=webweather05m |work=The Seattle Times |access-date=July 14, 2020}}</ref><ref>{{cite press release |date=December 7, 2007 |title=Interstate 5 Reopens to All Traffic Through Chehalis, Highways Still Closed Elsewhere in the State |url=http://www.wsdot.wa.gov/News/2007/12/07_I5_open_Chehalis.htm |publisher=Washington State Department of Transportation |archive-url=https://web.archive.org/web/20080706194237/http://www.wsdot.wa.gov/News/2007/12/07_I5_open_Chehalis.htm |archive-date=July 6, 2008 |access-date=August 10, 2008}}</ref>

WSDOT was also allocated funding from the 2003 and 2005 packages to repair bridges on I-5 and add [[cable barrier]]s to sections of I-5 in Lewis, Skagit, Snohomish, and Whatcom counties.<ref>{{cite report |last1=Olson |first1=Dave |last2=Sujka |first2=Mark |last3=Manchas |first3=Brad |date=June 2013 |title=Cable Median Barrier Program in Washington State (WA-RD 812.1) |pages=8, 34 |url=https://www.wsdot.wa.gov/research/reports/fullreports/812.1.pdf |publisher=Washington State Department of Transportation |access-date=July 14, 2020}}</ref> A section through Marysville was later upgraded to a concrete barrier in 2010 after several fatal crossover collisions despite a reduction in the speed limit to {{convert|60|mph|kph|abbr=on}}.<ref>{{cite news |last=Sheets |first=Bill |date=January 21, 2010 |title=Heavy-duty I-5 barriers going up through Marysville |url=https://www.heraldnet.com/news/heavy-duty-i-5-barriers-going-up-through-marysville/ |work=The Everett Herald |access-date=July 14, 2020}}</ref> Other parts of the packages funded seismic retrofitting for bridges and overpasses, and the implementation of [[smart highway]] technology in 2010 that included [[variable speed limit]] signs in the Seattle area.<ref>{{cite news |last=Lindblom |first=Mike |date=November 7, 2010 |title=I-5 'smart signs' cut crashes, not travel times |url=http://seattletimes.nwsource.com/html/localnews/2013373837_smartsigns08m.html |work=The Seattle Times |archive-url=https://web.archive.org/web/20110114014724/http://seattletimes.nwsource.com/html/localnews/2013373837_smartsigns08m.html |archive-date=January 14, 2011 |access-date=July 15, 2020}}</ref><ref>{{cite news |last=Ryan |first=John |date=March 23, 2016 |title=Hollow Columns Holding Up I-5, I-405 Bridges Could Implode In Major Quake |url=https://kuow.org/stories/hollow-columns-holding-i-5-i-405-bridges-could-implode-major-quake/ |publisher=KUOW |access-date=July 15, 2020}}</ref> In May 2023, a third northbound lane from Seneca Street to Olive Way and ramp meters for the collector–distributor lanes and the Cherry Street onramp were added to I-5 to improve weaving.<ref>{{cite news |last=Lindblom |first=Mike |date=May 17, 2021 |title=Work gets underway to ease an I-5 bottleneck in downtown Seattle |url=https://www.seattletimes.com/seattle-news/transportation/work-gets-underway-to-ease-an-i-5-bottleneck-in-downtown-seattle/ |work=The Seattle Times |access-date=May 17, 2021}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=August 1, 2023 |title=Seattle's I-5 squeeze finally not so tight as new lane opens |url=https://www.seattletimes.com/seattle-news/transportation/seattles-i-5-squeeze-finally-not-so-tight-as-new-lane-opens/ |work=The Seattle Times |accessdate=August 1, 2023}}</ref>

===Incidents and closures===
[[File:2017 Cascades derailment aerial view from NTSB preliminary report.jpg|thumb|right|Aerial view of the [[2017 Washington train derailment|2017 Amtrak derailment]] over southbound I-5 in [[DuPont, Washington|DuPont]]]]

On May 23, 2013, the northernmost span of the [[Skagit River]] bridge between Mount Vernon and Burlington [[I-5 Skagit River Bridge collapse|collapsed]] after a [[semi-trailer truck]] struck an overhead beam.<ref>{{cite news |last1=Fiege |first1=Gale |last2=Stevick |first2=Eric |date=May 23, 2013 |title=Everyone safe after bridge over Skagit River collapses |work=The Everett Herald |url=http://www.heraldnet.com/article/20130523/NEWS01/305239999 |archive-url=https://web.archive.org/web/20150617040427/http://www.heraldnet.com/article/20130523/NEWS01/305239999 |archive-date=June 17, 2015 |access-date=October 7, 2018}}</ref> The collapse caused two vehicles to fall into the river, where all three people were later rescued with minor injuries.<ref>{{cite news |date=May 23, 2013 |title='Miracles': 3 survive I-5 collapse |url=http://seattletimes.com/html/localnews/2021045926_bridgecollapsexml.html |work=The Seattle Times |archive-url=https://web.archive.org/web/20131015205445/http://seattletimes.com/html/localnews/2021045926_bridgecollapsexml.html |archive-date=October 15, 2013 |access-date=July 14, 2020}}</ref> The incident triggered a [[state of emergency]] and discussions about the state of national infrastructure. A temporary span was assembled using prefabricated steel sections and opened to limited traffic on June 19, 2013.<ref>{{cite web |last=Long |first=Priscilla |date=September 16, 2013 |title=I-5 Skagit River Bridge at Mount Vernon collapses on May 23, 2013. |url=http://historylink.org/File/10584 |work=HistoryLink |access-date=October 7, 2018}}</ref><ref>{{cite news |date=June 19, 2013 |title=Skagit River Bridge reopens |url=https://www.goskagit.com/news/local_news/skagit-river-bridge-reopens/article_83fee046-d8ee-11e2-8a3a-001a4bcf887a.html |work=Skagit Valley Herald |location=Mount Vernon, Washington |access-date=July 14, 2020}}</ref> A permanent replacement for the span was built west of the bridge and slid into place before opening to traffic on September 15, 2013.<ref>{{cite news |last=DeMay |first=Daniel |date=September 15, 2013 |title=Skagit River Bridge span moves into place |url=https://www.goskagit.com/local/skagit-river-bridge-span-moves-into-place/article_e1ea3b73-2d0d-51b6-9216-e193dd62ef5e.html |work=Skagit Valley Herald |location=Mount Vernon, Washington |access-date=July 14, 2020}}</ref>

A section of I-5 was closed for several hours on December 18, 2017, after an Amtrak ''Cascades'' passenger train [[2017 Washington train derailment|derailed]] onto the southbound lanes near DuPont. The train had been on the inaugural trip on the new [[Point Defiance Bypass]] route, constructed along the freeway between [[Nisqually, Washington|Nisqually]] and [[Tacoma Dome Station]], which was subsequently closed.<ref>{{cite news |last1=Pearce |first1=Matt |last2=Nelson |first2=Laura J. |date=December 18, 2017 |title=Amtrak train derails over I-5 in Washington state; 3 people killed |url=http://www.latimes.com/nation/nationnow/la-na-washington-train-derailment-20171218-story.html |work=[[Los Angeles Times]] |access-date=December 18, 2017}}</ref> The derailment, which killed three passengers and injured more than 70 others, was caused by high speeds on a curved section of track approaching the I-5 overpass.<ref>{{cite news |last1=Malas |first1=Nour |last2=Elinson |first2=Zusha |date=December 19, 2017 |title=Derailed Amtrak Train Was Traveling at 80 MPH in a 30 MPH Zone |url=https://www.wsj.com/articles/derailed-amtrak-train-was-traveling-at-80-m-p-h-before-crash-1513672712 |work=[[The Wall Street Journal]] |access-date=July 14, 2020}}</ref>

The Seattle section of I-5 has been the site of several large protests and demonstrations since its construction.<ref>{{cite news |last=Berger |first=Knute |author-link=Knute Berger |date=June 5, 2020 |title=A short, violent history of Puget Sound uprisings, protests and riots |url=https://crosscut.com/2020/06/short-violent-history-puget-sound-uprisings-protests-and-riots |work=Crosscut.com |access-date=July 14, 2020}}</ref> A demonstration against the [[Cambodian campaign|U.S. invasion of Cambodia]] at the University of Washington on May 5, 1970, held in response to the [[Kent State shootings]], culminated in 5,000 protesters marching onto the Ship Canal Bridge en route to Downtown Seattle.<ref>{{cite news |last=Hannula |first=Don |date=May 5, 1970 |title=5,000 U.W. Protesters Block Traffic on Freeway |page=1 |work=The Seattle Times}}</ref> An attempted protest on the freeway the following day was stopped by local police and state troopers armed with [[tear gas]] and clubs. The city government sanctioned a march in the express lanes on May 8 that was attended by 15,000 people as other protests continued for several days.<ref>{{cite web |last=Crowley |first=Walt |date=January 1, 2000 |title=Antiwar protesters block Interstate 5 in Seattle on May 5, 1970. |url=https://www.historylink.org/File/1994 |work=HistoryLink |access-date=July 14, 2020}}</ref><ref>{{cite news |last=Hannula |first=Don |date=May 9, 1970 |title=City Calm as Protests Subside |page=1 |work=The Seattle Times}}</ref> The [[1999 Seattle WTO protests|1999 WTO Conference protests]] included minor disruptions to I-5 traffic while police blocked access from ramps in Downtown Seattle.<ref>{{cite news |last=Sunde |first=Scott |date=November 30, 1999 |title=It's protest city—and get ready for the big one today |page=A1 |work=Seattle Post-Intelligencer}}</ref> Several [[Black Lives Matter]] protests in 2014, 2016, and 2020 resulted in long nighttime shutdowns of the freeway in Seattle and Olympia.<ref>{{cite news |date=November 25, 2014 |title=In Seattle, a march, 'die-ins' and police pelted with rocks |url=https://www.seattletimes.com/seattle-news/in-seattle-a-march-lsquodie-insrsquo-and-police-pelted-with-rocks/ |work=The Seattle Times |access-date=July 14, 2020}}</ref><ref>{{cite news |last=Dickson |first=Amelia |date=July 7, 2016 |title=Olympia demonstrators cause damage, clog I-5 on-ramp in protest |url=https://www.theolympian.com/news/local/article88372257.html |work=The Olympian |access-date=July 14, 2020}}</ref> The 2020 [[George Floyd protests in Washington (state)|George Floyd protests]] included over a month of nightly protests on I-5 with a non-intervention policy implemented by the Washington State Patrol and precautionary closures.<ref>{{cite news |last=Sullivan |first=Chris |date=June 18, 2020 |title=Washington State Patrol plans to keep shutting down I-5 for protests |url=https://mynorthwest.com/1961268/washington-state-patrol-plans-to-keep-shutting-down-i-5-for-protesters/ |publisher=KIRO Radio |access-date=July 14, 2020}}</ref> The non-intervention policy was suspended after a July 4 incident in which a driver evaded the blockades and struck two protesters on I-5, killing one.<ref>{{cite news |last1=Bazzaz |first1=Dahlia |last2=Fields |first2=Asia |last3=Lacitis |first3=Erik |date=July 4, 2020 |title=1 protester dead, 1 injured after man drives into protesters on I-5 in Seattle |url=https://www.seattletimes.com/seattle-news/2-people-hit-by-car-on-i-5-in-downtown-seattle-during-protest/ |work=The Seattle Times |access-date=July 14, 2020}}</ref><ref>{{cite news |last=Waller |first=Allyson |date=July 6, 2020 |title=Seattle Protester Dies After Being Struck by Car |page=A16 |url=https://www.nytimes.com/2020/07/05/us/summer-taylor-seattle.html |work=The New York Times |access-date=July 14, 2020}}</ref>

===Future projects and proposals===
[[File:InterstateBridge.jpg|thumb|right|The [[Interstate Bridge]], a pair of movable bridges that carry I-5 over the [[Columbia River]], are planned to be replaced in the 2020s]]

Within the Puget Sound region, preservation and maintenance of I-5 is expected to cost $2.5&nbsp;billion between 2020 and 2040, and substantial rebuilding of the freeway will be required.<ref>{{cite news |last=Slager |first=Melissa |date=January 12, 2018 |title=Traffic's going to worsen, but don't worry, there's a $40B plan |url=https://www.heraldnet.com/news/council-issues-updated-vision-2040-with-40b-recommendation/ |work=The Everett Herald |access-date=September 11, 2018}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=March 13, 2008 |title=No new state money requested for cracked, clogged Seattle stretch |url=https://archive.seattletimes.com/archive/20080313/i5funding13m/no-new-state-money-requested-for-cracked-clogged-seattle-stretch |work=The Seattle Times |access-date=September 11, 2018}}</ref> WSDOT began extensive repaving of the highway in the Seattle area in the 2010s, alongside repairs to [[expansion joint]]s and other deteriorating structures during weekend closures.<ref>{{cite news |last=Gutman |first=David |date=April 17, 2017 |title=I-5 repaving starts this week: 3 years, 22 miles, 'some rough commutes' |url=https://www.seattletimes.com/seattle-news/transportation/northbound-i-5-repaving-starts-this-week-3-years-22-miles-some-rough-commutes/ |work=The Seattle Times |access-date=July 13, 2020}}</ref><ref>{{cite web |title=Revive I-5: Preserving the freeway |url=https://www.wsdot.wa.gov/projects/i5/revive/home |publisher=Washington State Department of Transportation |access-date=July 13, 2020 |archive-date=July 14, 2020 |archive-url=https://web.archive.org/web/20200714085717/https://www.wsdot.wa.gov/projects/i5/revive/home |url-status=dead }}</ref> Pavement replacement and expansion joint repairs on the section between Yesler Way and North 117th Street in Seattle is expected to begin in 2023 and take four years to complete.<ref>{{cite web |title=I-5/Yesler Way to NE 117th St. – Pavement, Deck, and Expansion Joints |url=https://wsdot.wa.gov/construction-planning/search-projects/i-5-yesler-way-ne-117th-st-pavement-deck-and-expansion-joints |publisher=Washington State Department of Transportation |access-date=September 19, 2022}}</ref> Portions of the freeway's [[Right-of-way (property access)|right-of-way]] will be used for extensions of Sound Transit's [[Link light rail]] system, which is planned to extend north to Lynnwood and south to Federal Way by 2025.<ref>{{cite web |date=September 2018 |title=Lynnwood Link Extension |url=https://www.soundtransit.org/sites/default/files/project-documents/lynnwood-link-extension-folio-201809.pdf |publisher=Sound Transit |access-date=September 11, 2018}}</ref><ref>{{cite press release |date=July 23, 2015 |title=Sound Transit Board identifies preferred alternative for light rail extension to Kent/Des Moines, Federal Way |url=https://www.soundtransit.org/About-Sound-Transit/News-and-events/News-releases/sound-transit-board-identifies-preferred |publisher=Sound Transit |access-date=September 11, 2018}}</ref> As part of the reconstruction of [[Washington State Route 520|SR&nbsp;520]], a new HOV ramp from the I-5 reversible lanes to SR&nbsp;520 is planned to be opened in early 2024, alongside a fifth reversible lane for HOVs that extends south to Mercer Street.<ref>{{cite news |last=Lindblom |first=Mike |date=September 26, 2018 |title=I-5 will add a 5th express lane to serve future Eastside-South Lake Union bus routes |url=https://www.seattletimes.com/seattle-news/transportation/i-5-will-add-a-5th-express-lane-to-serve-future-eastside-south-lake-union-bus-routes/ |work=The Seattle Times |access-date=September 26, 2018}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=November 16, 2022 |title=A crumbling Highway 520 ramp support needs a do-over |url=https://www.seattletimes.com/seattle-news/transportation/a-crumbling-highway-520-ramp-support-needs-a-do-over/ |work=The Seattle Times |access-date=November 23, 2022}}</ref>

The 2015 Connecting Washington transportation funding package included allocations for several major projects on I-5, among them an expansion in the Joint Base Lewis–McChord area and several new and reconstructed interchanges in Lacey and Marysville. Widening of an {{convert|8|mi|km|adj=mid|spell=in}} section through the military base and neighboring DuPont to eight lanes began in October 2018 and is planned to be completed in 2025;<ref>{{cite news |last=Ocker |first=Kenny |date=September 30, 2018 |title=WSDOT is going to add lanes to Interstate 5 near JBLM. What's the catch? |url=https://www.thenewstribune.com/news/local/traffic/article219143295.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 14, 2020}}</ref> the project also includes reconstruction of several interchanges and accommodations for the adjacent Point Defiance Bypass railroad corridor.<ref>{{cite news |last=Schrader |first=Jordan |date=August 29, 2015 |title=Wider I-5 — along with years of worse congestion — coming to JBLM area |url=https://www.thenewstribune.com/news/local/traffic/article32730132.html |work=The News Tribune |location=Tacoma, Washington |access-date=July 13, 2020}}</ref><ref>{{cite news |last=McKay |first=Bud |date=September 1, 2018 |title=Interstate 5 widening project by JBLM moves into stage 2 |url=https://www.army.mil/article/210617/interstate_5_widening_project_by_jblm_moves_into_stage_2 |publisher=U.S. Army |access-date=July 14, 2020}}</ref> The [[Washington State Route 510|SR&nbsp;510]] interchange in Lacey was reconstructed into the state's first [[diverging diamond interchange]], which opened in 2020.<ref>{{cite news |last=Boone |first=Rolf |date=August 3, 2020 |title=Long awaited 'diverging diamond' interchange opens in Lacey |url=https://www.theolympian.com/news/local/article244694467.html |work=The Olympian |access-date=August 3, 2020}}</ref>

The northbound HOV lane is planned to be extended from Everett to Marysville by late 2024 as part of a $123&nbsp;million retrofit project that began construction in 2022.<ref>{{cite news |last=Watanabe |first=Ben |date=May 28, 2023 |title=$123M project starting on Highway 529 interchange, I-5 HOV lane |url=https://www.heraldnet.com/news/123m-project-starting-on-highway-529-interchange-i-5-hov-lane/ |work=The Everett Herald |accessdate=June 8, 2023}}</ref> It will also include an expansion of the SR&nbsp;529 interchange in southern Marysville into a full interchange to provide a bypass for a congested railroad crossing on SR&nbsp;528.<ref>{{cite news |last=Watanabe |first=Ben |date=March 2, 2023 |title=Work on I-5 HOV lane from Everett to Marysville starts next week |url=https://www.heraldnet.com/news/work-on-i-5-hov-lane-from-everett-to-marysville-starts-next-week/ |work=The Everett Herald |access-date=March 2, 2023}}</ref><ref>{{cite news |last=Winters |first=Chris |date=February 7, 2015 |title=New I-5 interchange planned for Marysville |url=https://www.heraldnet.com/news/new-i-5-interchange-planned-for-marysville/ |work=The Everett Herald |access-date=September 11, 2018}}</ref> A new interchange at 156th Street in northern Marysville is planned to open in the late 2020s.<ref>{{cite news |date=October 19, 2015 |title=State plans new I-5 interchange near Smokey Point |url=https://www.heraldnet.com/news/state-plans-new-i-5-interchange-near-smokey-point/ |work=The Everett Herald |access-date=October 6, 2018}}</ref><ref>{{cite web |title=Connecting Washington |url=https://www.wsdot.wa.gov/construction-planning/funding/connecting-washington |publisher=Washington State Department of Transportation |access-date=September 11, 2018}}</ref> The Puget Sound Gateway Program, scheduled to be completed in 2028 will include the construction of two interchanges on I-5, at the Port of Tacoma to serve a realigned SR&nbsp;167 and near SeaTac for an extension of [[Washington State Route 509|SR&nbsp;509]].<ref>{{cite news |last=Peterson |first=Josephine |date=June 22, 2020 |title=Federal funding for construction on highways 167 and 509 aims to reduce local traffic |url=https://www.thenewstribune.com/news/local/community/puyallup-herald/ph-news/article243651107.html |work=The News Tribune |access-date=July 10, 2020}}</ref>

The Vancouver section of I-5 was planned to be rebuilt as part of the [[Columbia River Crossing]] program, which would have replaced the six-lane [[Interstate Bridge]] with a wider bridge at a cost of approximately $3.4&nbsp;billion. The northern approach to the bridge would have included a collector–distributor system with a maximum width of 16 lanes. The program was cancelled in 2013 after $175&nbsp;million had been spent planning because of opposition within the Washington state legislature, but the bridge proposal has been revived several times since.<ref>{{cite news |last=Hernton |first=Hal |date=July 1, 2013 |title=State Senate deadlock kills Columbia Crossing |url=http://old.seattletimes.com/html/localnews/2021308733_bridgedemisexml.html |work=The Seattle Times |access-date=September 11, 2018 |archive-url=https://web.archive.org/web/20180912092256/http://old.seattletimes.com/html/localnews/2021308733_bridgedemisexml.html |archive-date=September 12, 2018 }}</ref> A new panel of legislators from both states was convened in 2018 to study the bridge project, with funding to continue planning work in time for federal deadlines on loan repayment.<ref>{{cite news |last=Mize |first=Jeffrey |date=October 13, 2019 |title=New I-5 Bridge project: Here we go, again...again |url=https://www.columbian.com/news/2019/oct/13/new-i-5-bridge-project-here-we-go-again-again/ |work=The Columbian |access-date=July 7, 2020}}</ref> Oregon and Washington plan to submit an environmental review in 2023 and begin construction in 2025 if funding is found for the project.<ref>{{cite news |last=Seekamp |first=William |date=July 21, 2022 |title=I-5 Bridge Replacement Program moves into environmental review phase |url=https://www.columbian.com/news/2022/jul/21/i-5-bridge-replacement-program-moves-into-environmental-review-phase/ |work=The Columbian |access-date=February 1, 2023}}</ref><ref>{{cite news |last=Theen |first=Andrew |date=September 24, 2019 |title=Oregon and Washington: We'll start building a new Interstate Bridge by 2025 |url=https://www.oregonlive.com/commuting/2019/09/oregon-and-washington-well-start-building-a-new-interstate-bridge-by-2025.html |work=The Oregonian |access-date=July 7, 2020}}</ref> The bridge replacement is expected to cost up to $2.45&nbsp;billion, while the entire program—including reconstruction of several interchanges and transit improvements—is estimated to cost $5.5&nbsp;billion to $7.5&nbsp;billion.<ref>{{cite news |last=Seekamp |first=William |date=February 27, 2023 |title=Up to $2.45 billion of I-5 Bridge project budget will go to actual replacement |url=https://www.columbian.com/news/2023/feb/27/up-to-2-45-billion-of-i-5-bridge-project-budget-will-go-to-actual-replacement/ |work=The Columbian |access-date=March 1, 2023}}</ref><ref>{{cite news |last=Seekamp |first=William |date=December 9, 2022 |title=New I-5 Bridge cost: Likely $6 Billion |url=https://www.columbian.com/news/2022/dec/09/new-i-5-bridge-cost-likely-6-billion/ |work=The Columbian |access-date=December 10, 2022}}</ref>

==Exit list==
{{jcttop|exit|length_ref=<ref name="log"/>}}
{{Jctint|exit
|river=[[Columbia River]]
|lspan=2
|mile=0.00
|mspan=2
|exit=—
|road={{Jct|state=OR|I|5|dir1=south|city1=Portland}}
|notes=Continuation into Oregon
}}
{{jctbridge|exit
|mile=none
|bridge=[[Interstate Bridge]]
}}
{{WAint|exit
|county=Clark
|cspan=15
|location=Vancouver
|lspan=6
|mile=0.41
|exit=1A
|road={{jct|state=WA|SR|14|dir1=east|LCT||city1=Camas}}
|notes=}}
{{WAint|exit
|mile=0.45
|exit=1B
|type=incomplete
|road=6th Street&nbsp;– [[Vancouver, Washington|Vancouver City Center]], Convention Center
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=1.05
|exit=1C
|road={{jct|state=WA|SR|501|name1=Mill Plain Boulevard|location1=[[Vancouver, Washington|Vancouver City Center]]}}, [[Port of Vancouver USA|Port of Vancouver]]
|notes=}}
{{WAint|exit
|mile=1.58
|exit=1D
|road=4th Plain Boulevard
|notes=}}
{{WAint|exit
|mile=2.35
|exit=2
|road={{jct|state=WA|SR|500|dir1=east|road|39th Street}}
|notes=}}
{{WAint|exit
|mile=3.07
|exit=3
|road=Northeast Highway&nbsp;99, Main Street
|notes=}}
{{WAint|exit
|location=none
|mile=4.36
|exit=4
|road=Northeast 78th Street
|notes=}}
{{WAint|exit
|location=none
|mile=5.39
|exit=5
|road=Northeast 99th Street
|notes=}}
{{WAint|exit
|location=none
|mile=7.24
|exit=7A
|type=incomplete
|road=Northeast 134th Street&nbsp;– [[Washington State University Vancouver]]
|notes=Northbound exit&nbsp;and southbound entrance; southbound exit&nbsp;is via I-205 (exit 36)}}
{{WAint|exit
|location=none
|mile=7.47
|type=incomplete
|exit=7B
|road=Northeast 139th Street
|notes=No southbound exit}}
{{WAint|exit
|location=none
|mile=7.50
|exit=7
|type=incomplete
|road={{jct|state=WA|I|205|dir1=south|to2=yes|I|84|SR|14|road|Northeast 134th Street|location1=[[Salem, Oregon|Salem]]|location2=[[Washington State University Vancouver]]}}
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint|exit
|location=none
|mile=9.51
|exit=9
|road=Northeast 179th Street&nbsp;– [[Clark County Fair|Clark County Event Center]]
|notes=}}
{{WAint|exit
|location=none
|mile=11.20
|exit=11
|road={{jct|state=WA|SR|502|dir1=east|name1=Northeast 219th Street|city1=Battle Ground}}
|notes=}}
{{WAint|exit
|location=Ridgefield
|mile=14.21
|exit=14
|road={{jct|state=WA|SR|501|dir1=south|name1=Pioneer Street|city1=Ridgefield}}
|notes=}}
{{WAint|exit
|location=La Center
|mile=16.80
|exit=16
|road=Northwest La Center Road&nbsp;– [[La Center, Washington|La Center]], [[Cowlitz Indian Tribe|Cowlitz Reservation]]
|notes=}}
{{WAint|exit
|county=Cowlitz
|cspan=15
|location=Woodland
|lspan=2
|mile=21.08
|exit=21
|road={{jct|state=WA|SR|503|dir1=east|city1=Woodland|city2=Cougar}}
|notes=}}
{{WAint|exit
|mile=22.72
|exit=22
|road=Dike Access Road
|notes=}}
{{WAint|exit
|location=none
|mile=27.70
|exit=27
|road=Todd Road&nbsp;– [[Port of Kalama]]
|notes=}}
{{WAint|exit
|location=Kalama
|mile=29.84
|mile2=30.64
|exit=30
|road=[[Kalama, Washington|Kalama]]
|notes=}}
{{WAint|exit
|location=none
|mile=32.28
|exit=32
|road=Kalama River Road
|notes=}}
{{WAint|exit
|location=Kelso
|lspan=5
|mile=36.97
|type=incomplete
|exit=36A
|road=Kelso Drive
|notes=No southbound exit}}
{{WAint|exit
|mile=36.97
|exit=36
|road=Talley Way&nbsp;– Kelso Industrial Area
|notes=Signed as exits 36B northbound and 36A southbound}}
{{WAint|exit
|mile=36.97
|exit=36
|road={{jct|state=WA|SR|432|dir1=west|to2=to|SR|4|US|30|city1=Longview|city2=Long Beach|city3=Kelso}}
|notes=}}
{{WAint|exit
|mile=39.88
|exit=39
|road={{jct|state=WA|SR|4|dir1=west|LCT||city1=Kelso|name1=Allen Street}}
|notes=}}
{{WAint|exit
|mile=40.77
|exit=40
|road=North Kelso Avenue&nbsp;– [[Lower Columbia College]], [[Long Beach, Washington|Long Beach]]
|notes=}}
{{WAint|exit
|location=none
|mile=42.73
|exit=42
|road=Lexington Bridge Drive
|notes=}}
{{WAint|exit
|location=none
|mile=46.20
|exit=46
|road=Headquarters Road, Pleasant Hill Road
|notes=}}
{{WAint|exit
|location=Castle Rock
|lspan=2
|mile=48.04
|exit=48
|road={{jct|state=WA|BL|5|dir1=north|dab1=Castle Rock|city1=Castle Rock|name1=Huntington Avenue}}
|notes=}}
{{WAint|exit
|mile=49.91
|exit=49
|road={{jct|state=WA|SR|411|dir1=south|SR|504|dir2=east|city1=Castle Rock|city2=Toutle|location3=[[Mount St. Helens National Volcanic Monument]]|name1=[[Interstate 5 Business (Castle Rock, Washington)|I-5 Bus.]] south}}
|notes=}}
{{WAint|exit
|location=none
|mile=52.72
|exit=52
|road=Barnes Drive, Toutle Park Road
|notes=}}
{{WAint|exit
|county=Lewis
|cspan=13
|location=none
|mile=57.41
|exit=57
|road=Jackson Highway, Barnes Drive
|notes=}}
{{WAint|exit
|location=none
|mile=59.27
|exit=59
|road={{jct|state=WA|SR|506|dir1=west|city1=Vader|city2=Ryderwood}}
|notes=}}
{{WAint|exit
|location=none
|mile=60.98
|exit=60
|road={{jct|state=WA|SR|506|dir1=west|name1=Toledo Vader Road}}
|notes=}}
{{WAint|exit
|location=none
|mile=63.49
|exit=63
|road={{jct|state=WA|SR|505|city1=Winlock|city2=Toledo}}
|notes=}}
{{WAint|exit
|location=none
|mile=68.48
|exit=68
|type=concur
|road={{jct|state=WA|US|12|dir1=east|city1=Morton|city2=Yakima}}
|notes=South end of US&nbsp;12 overlap}}
{{WAint|exit
|location=Napavine
|lspan=2
|mile=71.12
|exit=71
|road={{jct|state=WA|SR|508|dir1=east|city1=Napavine|city2=Onalaska}}
|notes=}}
{{WAint|exit
|mile=72.85
|exit=72
|road=Rush Road
|notes=}}
{{WAint|exit
|location=Chehalis
|lspan=4
|mile=74.78
|exit=74
|road=Labree Road
|notes=}}
{{WAint|exit
|mile=76.62
|exit=76
|road=13th Street
|notes=}}
{{WAint|exit
|mile=78.04
|exit=77
|road={{jct|state=WA|SR|6|dir1=west|city1=Pe Ell|city2=Raymond}}
|notes=}}
{{WAint|exit
|mile=79.15
|exit=79
|road=Chamber Way
|notes=}}
{{WAint|exit
|location=Centralia
|lspan=2
|mile=81.74
|exit=81
|road={{jct|state=WA|SR|507|dir1=north|name1=Mellen Street|location1=[[Centralia, Washington|Centralia City Center]]}}
|notes=Southbound access is via exit 82}}
{{WAint|exit
|mile=82.80
|exit=82
|road=Harrison Avenue, Factory Outlet Way
|notes=}}
{{WAint|exit
|county=Thurston
|cspan=16
|location=none
|mile=88.40
|exit=88
|type=concur
|road={{jct|state=WA|US|12|dir1=west|city1=Aberdeen|city2=Tenino}}
|notes=North end of US&nbsp;12 overlap}}
{{WAint|exit
|location=none
|mile=95.28
|exit=95
|road={{jct|state=WA|SR|121|dir1=north|city1=Littlerock|city2=Maytown}}
|notes=}}
{{WAint|exit
|location=Tumwater
|lspan=5
|mile=99.35
|exit=99
|road={{jct|state=WA|SR|121|dir1=south|name1=93rd Avenue Southwest}}
|notes=}}
{{WAint|exit
|mile=101.37
|exit=101
|road=Tumwater Boulevard&nbsp;– [[Olympia Regional Airport]]
|notes=}}
{{WAint|exit
|mile=102.86
|exit=102
|road=Trosper Road&nbsp;– [[Black Lake (Washington)|Black Lake]]
|notes=}}
{{WAint|exit
|mile=104.05
|exit=103
|type=incomplete
|road=Deschutes Way, 2nd Avenue
|notes=No southbound entrance}}
{{WAint|exit
|mile=104.39
|exit=104
|road={{jct|state=WA|US|101|dir1=north|city1=Aberdeen|city2=Port Angeles}}
|notes=}}
{{WAint|exit
|location=Olympia
|lspan=6
|mile=105.52
|exit=105A
|road=[[Washington State Capitol|State Capitol]], [[Olympia, Washington|Olympia City Center]]
|notes=Signed as exit&nbsp;105 northbound}}
{{WAint|exit
|mile=105.82
|exit=105B
|road=[[Port of Olympia]]
|notes=Signed as exit&nbsp;105 northbound}}
{{WAint|exit
|mile=107.52
|exit=107
|road=Pacific Avenue
|notes=}}
{{WAint|exit
|mile=108.46
|exit=108A
|type=incomplete
|road=Sleater–Kinney Road south
|notes=No northbound entrance; signed as exit&nbsp;108 southbound}}
{{WAint|exit
|mile=108.46
|exit=108B
|type=incomplete
|road=Sleater–Kinney Road north
|notes=No northbound entrance; southbound exit&nbsp;is via exit&nbsp;109}}
{{WAint|exit
|mile=108.96
|exit=108C
|type=incomplete
|road=College Street
|notes=Northbound exit&nbsp;only}}
{{WAint|exit
|location=Lacey
|lspan=2
|mile=109.19
|exit=109
|road=Martin Way
|notes=}}
{{WAint|exit
|mile=112.01
|exit=111
|road={{jct|state=WA|SR|510|dir1=east|name1=Marvin Road|city1=Yelm}}
|notes=}}
{{WAint|exit
|location=none
|mile=114.36
|exit=114
|road=[[Nisqually, Washington|Nisqually]]
|notes=}}
{{WAint|exit
|county=Pierce
|cspan=19
|location=none
|mile=116.77
|exit=116
|road=Mounts Road&nbsp;– [[Old Nisqually, Washington|Old Nisqually]]
|notes=}}
{{WAint|exit
|location=DuPont
|lspan=2
|mile=118.02
|exit=118
|road=Center Drive&nbsp;– [[DuPont, Washington|DuPont City Center]]
|notes=}}
{{WAint|exit
|mile=119.07
|exit=119
|road=Steilacoom–DuPont Road
|notes=}}
{{Jctint|exit
|location_special=[[Joint Base Lewis–McChord]]
|mile=120.93
|exit=120
|road=41st Division Drive&nbsp;– [[Joint Base Lewis–McChord]]
|notes=}}
{{WAint|exit
|location=Lakewood
|lspan=5
|mile=122.74
|exit=122
|road=Berkeley Street
|notes=}}
{{WAint|exit
|mile=123.64
|exit=123
|road=Thorne Lane
|notes=}}
{{WAint|exit
|mile=124.70
|exit=124
|road=Gravelly Lake Drive
|notes=}}
{{WAint|exit
|mile=125.92
|exit=125
|road=Bridgeport Way&nbsp;– [[McChord Field]]
|notes=}}
{{WAint|exit
|mile=127.54
|exit=127
|road={{jct|state=WA|SR|512|dir1=east|city1=Puyallup|road|South Tacoma Way}}
|notes=}}
{{WAint|exit
|location=none
|mile=128.98
|exit=128
|type=incomplete
|road=South 84th Street
|notes=Southbound exit&nbsp;is via exit&nbsp;129}}
{{WAint|exit
|location=Tacoma
|lspan=6
|mile=129.65
|exit=129
|road=South 72nd Street, South 74th Street, South 84th Street
|notes=}}
{{WAint|exit
|mile=130.75
|exit=130
|road=South 56th Street, Tacoma Mall Boulevard&nbsp;– [[University Place, Washington|University Place]]
|notes=}}
{{WAint|exit
|mile=131.89
|exit=132
|road={{jct|state=WA|SR|16|dir1=west|name1=South 38th Street|city1=Gig Harbor|city2=Bremerton|location3=[[Tacoma Mall]]}}
|notes=}}
{{WAint|exit
|mile=133.76
|exit=133
|road={{jct|state=WA|I|705|dir1=north|SR|7|dir2=south|name2=38th Street|road|East 26th Street|location1=[[Downtown Tacoma|Tacoma City Center]]}}
|notes=}}
{{WAint|exit
|mile=134.93
|exit=134
|type=incomplete
|road=Portland Avenue
|notes=Southbound exit&nbsp;is via exit&nbsp;135}}
{{WAint|exit
|mile=135.09
|exit=135
|road={{jct|state=WA|SR|167|dir1=north|city1=Puyallup}}
|notes=}}
{{WAint|exit
|location=Fife
|lspan=3
|mile=136.15
|exit=136
|road=20th Street East&nbsp;– [[Port of Tacoma]]
|notes=Signed as exits&nbsp;136A (20th Street) and 136B (Port of Tacoma) northbound}}
{{WAint|exit
|mile=137.51
|exit=137
|road={{jct|state=WA|SR|99|dir1=north|name1=54th Avenue East|city1=Fife}}
|notes=}}
{{WAint|exit
|mile=
|exit=138
|road=
{{jct|state=WA|SR|167|SR|509|dir1=south|dir2=north}}
|type=future
|notes=proposed}}
{{WAint|exit
|county=King
|cspan=47
|location=Federal Way
|lspan=3
|mile=142.06
|exit=142
|road={{jct|state=WA|SR|18|name1=South 348th Street|city1=Auburn}}
|notes=Signed as exits&nbsp;142A (east) and 142B (west) northbound}}
{{WAint|exit
|mile=143.89
|exit=143
|road=South 320th Street&nbsp;– [[Federal Way, Washington|Federal Way]]
|notes=}}
{{WAint|exit
|mile=144.08
|exit=♦
|type=hov
|road=South 317th Street
|notes=[[HOV]] only}}
{{WAint|exit
|location=Kent
|lspan=2
|mile=146.87
|exit=147
|road=South 272nd Street
|notes=}}
{{WAint|exit
|mile=149.23
|exit=149
|road={{jct|state=WA|SR|516|city1=Kent|city2=Des Moines}}
|notes=}}
{{WAint|exit
|location=SeaTac
|lspan=3
|mile=
|exit=150
|road={{jct|state=WA|SR-Toll|509|dir1=north|road|24th Avenue South}}
|type=unbuilt
|notes=Northbound exit and southbound entrance; under construction}}
{{WAint|exit
|mile=151.24
|exit=151
|road=Military Road, South 200th Street
|notes=}}
{{WAint|exit
|mile=152.32
|exit=152
|road=South 188th Street, Orillia Road South
|notes=}}
{{WAint|exit
|location=Tukwila
|lspan=7
|mile=154.19
|exit=153
|type=incomplete
|road=Southcenter Parkway&nbsp;– [[Tukwila, Washington|Tukwila]], [[Westfield Southcenter|Southcenter Mall]]
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=154.46
|exit=154A
|road={{jct|state=WA|SR|518|dir1=west|location1=[[Seattle–Tacoma International Airport|Sea-Tac Airport]]|city2=Burien|extra=airport}}
|notes=Signed as exit&nbsp;154B southbound}}
{{WAint|exit
|mile=154.46
|exit=154B
|road={{jct|state=WA|I|405|dir1=north|city1=Bellevue|city2=Renton}}
|notes=Signed as exit&nbsp;154A southbound}}
{{WAint|exit
|mile=154.71
|exit=154B
|type=incomplete
|road=Southcenter Boulevard&nbsp;– [[Westfield Southcenter|Southcenter Mall]]
|notes=Southbound exit&nbsp;and northbound entrance via Klickitat Drive}}
{{WAint|exit
|mile=156.00
|exit=156
|road={{jct|state=WA|SR|599|dir1=north|road|Interurban Avenue|city1=Tukwila}}
|notes=Split into two interchanges with some movements requiring the use of an interchange on SR&nbsp;599.}}
{{WAint|exit
|mile=157.40
|exit=157
|road={{jct|state=WA|SR|900|dir1=east|name1=[[Martin Luther King Jr. Way (Seattle)|M. L. King Way]]}}
|type=incomplete
|notes=No northbound exit to eastbound SR&nbsp;900; no southbound entrance from westbound SR&nbsp;900}}
{{WAint|exit
|mile=158.07
|exit=158
|road=Boeing Access Road, East Marginal Way, Airport Way
|notes=}}
{{WAint|exit
|location=Seattle
|lspan=29
|mile=161.27
|exit=161
|road=Swift Avenue, Albro Place
|notes=}}
{{WAint|exit
|mile=161.37
|mile2=161.60
|exit=162
|road=Corson Avenue, Michigan Street
|notes=}}
{{WAint|exit
|mile=163.03
|exit=163A
|road=Columbian Way, [[West Seattle Bridge]], Spokane Street&nbsp;– [[Lumen Field]], [[T-Mobile Park]]
|notes=Signed as exit&nbsp;163 northbound}}
{{WAint|exit
|mile=163.54
|exit=163B
|type=incomplete
|road=Forest Street, 6th Avenue South
|notes=Southbound exit&nbsp;only}}
{{WAint|exit
|mile=164.33
|exit=164
|type=incomplete
|road=Airport Way
|notes=Southbound exit&nbsp;only}}
{{WAint|exit
|mile=164.55
|exit=164A
|road={{jct|state=WA|I|90|dir1=east|city1=Bellevue|city2=Spokane}}
|notes=Signed as exit&nbsp;164 southbound; I-90 exits 2A-B eastbound, 2B-C westbound}}
{{WAint|exit
|mile=164.55
|exit=164B
|road=4th Avenue South, Airport Way, E. Martinez Drive (to [[Washington State Route 519|SR&nbsp;519]])&nbsp;– [[Colman Dock|Ferries]]
|notes=Signed as exit&nbsp;164 southbound}}
{{WAint|exit
|mile=164.68
|exit=164
|road=Dearborn Street
|notes=Signed as exit&nbsp;164A northbound; no southbound entrance}}
{{WAint|exit
|mile=165.35
|exit=—
|type=incomplete
|road=[[#Seattle express lanes|Express Lanes]]
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=165.38
|exit=165A
|road=James Street
|notes=Signed as exit&nbsp;164A northbound}}
{{WAint|exit
|mile=165.63
|exit=164A
|type=incomplete
|road=[[Madison Street (Seattle)|Madison Street]]&nbsp;– [[Seattle Convention Center|Convention Center]]
|notes=Northbound exit&nbsp;only}}
{{WAint|exit
|mile=165.75
|exit=165
|type=incomplete
|road=Seneca Street
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=165.81
|exit=165B
|type=incomplete
|road=Union Street
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint|exit
|mile=166.26
|exit=166
|type=incomplete
|road=Olive Way
|notes=Northbound exit&nbsp;and entrance}}
{{WAint|exit
|mile=166.42
|exit=166
|type=incomplete
|road=Stewart Street, [[Denny Way]]
|notes=Southbound exit&nbsp;and entrance}}
{{WAint|exit
|mile=166.97
|exit=167
|road=[[Mercer Street (Seattle)|Mercer Street]]&nbsp;– [[Seattle Center]]
|notes=}}
{{WAint|exit
|mile=167.73
|exit=168A
|type=incomplete
|road=Lakeview Boulevard
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=168.12
|exit=168B
|road={{jct|state=WA|SR|520|city1=Bellevue|city2=Kirkland}}
|notes=}}
{{WAint|exit
|mile=168.18
|exit=168A
|type=incomplete
|road=Boylston Avenue, Roanoke Street
|notes=Southbound exit&nbsp;and northbound entrance}}
{{jctbridge|exit
|mile=168.40
|mile2=169.07
|bridge=[[Ship Canal Bridge]]
}}
{{WAint|exit
|mile=169.44
|exit=169
|road=Northeast 45th Street
|notes=}}
{{WAint|exit
|mile=169.69
|exit=169
|road=Northeast 50th Street
|notes=}}
{{WAint|exit
|mile=170.31
|exit=170
|type=incomplete
|road=Ravenna Boulevard, Northeast 65th Street
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=170.70
|exit=171
|type=incomplete
|road=Northeast 71st Street, Northeast 65th Street
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint|exit
|mile=170.87
|exit=171
|type=incomplete
|road={{jct|state=WA|SR|522|name1=Lake City Way|city1=Bothell}}
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=171.56
|exit=172
|road=North 85th Street to Aurora Avenue North ([[Washington State Route 99|SR&nbsp;99]]), Northeast 80th Street
|notes=}}
{{WAint|exit
|mile=172.58
|exit=—
|type=incomplete
|road=[[#Seattle express lanes|Express Lanes]]
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint|exit
|mile=172.82
|exit=173
|road=Northgate Way, 1st Avenue Northeast
|notes=}}
{{WAint|exit
|mile=173.89
|exit=174
|type=incomplete
|road=Northeast 130th Street, Roosevelt Way
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|location1=Seattle
|location2=Shoreline
|location_group=city
|mile=174.64
|exit=175
|road={{jct|state=WA|SR|523|name1=Northeast 145th Street|road|5th Avenue Northeast}}
|notes=}}
{{WAint|exit
|location=Shoreline
|lspan=2
|mile=175.58
|exit=♦
|road=[[King County Metro|Metro Transit]] Base
|type=HOV
|notes=Buses and transit vehicles only}}
{{WAint|exit
|mile=176.19
|exit=176
|road=Northeast 175th Street&nbsp;– [[Shoreline, Washington|Shoreline]]
|notes=}}
{{WAint|exit
|county1=King
|county2=Snohomish
|location1=Shoreline
|location2=Mountlake Terrace
|location_group=city
|mile=177.81
|exit=177
|road={{jct|state=WA|SR|104|city1=Edmonds|city2=Lake Forest Park}}
|notes=}}
{{WAint|exit
|county=Snohomish
|cspan=27
|location=Mountlake Terrace
|lspan=2
|mile=178.33
|exit=178
|type=incomplete
|road=236th Street Southwest&nbsp;– [[Mountlake Terrace, Washington|Mountlake Terrace]]
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=179.35
|exit=179
|road=220th Street Southwest&nbsp;– [[Mountlake Terrace, Washington|Mountlake Terrace]]
|notes=}}
{{WAint|exit
|location=Lynnwood
|lspan=3
|mile=180.69
|exit=♦
|type=hov
|road=46th Avenue West ([[Lynnwood Transit Center|Lynnwood Park & Ride]])
|notes=HOV only}}
{{WAint|exit
|mile=180.77
|exit=181A
|type=incomplete
|road={{jct|state=WA|to1=To|SR|524|city1=Lynnwood|road|44th Avenue West}}
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=181.59
|exit=181B
|road={{jct|state=WA|SR|524|road|Alderwood Mall Parkway|name1=196th Street Southwest|city1=Lynnwood}}
|notes=Signed as exit&nbsp;181 southbound}}
{{WAint|exit
|location=none
|mile=182.67
|mspan=2
|exit=182
|espan=2
|road={{jct|state=WA|I|405|dir1=south|city1=Renton|city2=Bellevue}}
|notes=}}
{{WAint
|location=none
|mile=none
|type=incomplete
|road={{jct|state=WA|SR|525|dir1=north|to2=to|SR|99|city1=Mukilteo}}
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|location=none
|mile=183.96
|exit=183
|road=164th Street Southwest
|notes=}}
{{WAint|exit
|location=none
|mile=184.21
|exit=♦
|type=HOV
|road=Ash Way
|notes=Northbound exit&nbsp;and southbound entrance (buses only)}}
{{WAint|exit
|location=none
|mile=186.49
|exit=186
|road={{jct|state=WA|SR|96|dir1=east|road|128th Street Southwest|location1=[[Paine Field]]}}
|notes=}}
{{WAint|exit
|location=Everett
|lspan=8
|mile=187.80
|exit=♦
|type=hov
|road=112th Street Southeast&nbsp;– S. Everett Park & Ride
|notes=HOV only}}
{{WAint|exit
|mile=189.37
|exit=189
|road={{jct|state=WA|SR|99|dir1=south|SR|526|dir2=west|SR|527|dir3=south|name1=Everett Mall Way|road|Broadway|city1=Mukilteo|location2=[[Whidbey Island Ferry]]|location3=[[Paine Field]]|extra=ferry}}
|notes=}}
{{WAint|exit
|mile=192.51
|exit=♦
|type=hov
|road=Broadway
|notes=Northbound exit&nbsp;southbound entrance (HOV only)}}
{{WAint|exit
|mile=192.72
|exit=192
|road=41st Street (to Evergreen Way), Broadway
|notes=}}
{{WAint|exit
|mile=193.69
|exit=193
|type=incomplete
|road={{jct|state=WA|SR|529|name1=Pacific Avenue|location1=[[Downtown Everett|Everett City Center]]}}
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=193.98
|exit=194
|road={{jct|state=WA|US|2|dir1=east|city1=Snohomish|city2=Wenatchee}}
|notes=}}
{{WAint|exit
|mile=194.08
|exit=194
|type=incomplete
|road={{jct|state=WA|SR|529|name1=Everett Avenue|location1=[[Downtown Everett|Everett City Center]]}}
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint|exit
|mile=194.87
|exit=195
|type=incomplete
|road=Marine View Drive&nbsp;– [[Port of Everett]]
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|location=Marysville
|mile=198.33
|exit=198
|type=incomplete
|road={{jct|state=WA|SR|529|dir1=south|location1=[[Port of Everett]]|road|North Broadway}}
|notes=Southbound exit&nbsp;and northbound entrance}}
{{WAint|exit
|location1=Marysville
|location2=Tulalip
|lspan=3
|mile=199.17
|exit=199
|road={{jct|state=WA|SR|528|dir1=east|city1=Marysville|city2=Tulalip}}
|notes=}}
{{WAint|exit
|mile=200.84
|exit=200
|road=88th Street Northeast, Quil Ceda Way
|notes=}}
{{WAint|exit
|mile=202.52
|exit=202
|road=116th Street Northeast
|notes=}}
{{WAint|exit
|location1=Marysville
|location2=Arlington
|location_group=city
|mile=206.13
|exit=206
|road={{jct|state=WA|SR|531|name1=172nd Street Northeast}}
|notes=}}
{{WAint|exit
|location=Arlington
|mile=208.72
|exit=208
|road={{jct|state=WA|SR|530|dir1=east|city1=Arlington|city2=Darrington}}
|notes=}}
{{WAint|exit
|location=none
|mile=210.36
|exit=210
|road=236th Street Northeast
|notes=}}
{{WAint|exit
|location=none
|mile=212.71
|exit=212
|road={{jct|state=WA|SR|532|dir1=west|city1=Stanwood|location2=[[Camano Island]]}}
|notes=}}
{{WAint|exit
|location=none
|mile=215.09
|exit=215
|road=300th Street Northwest
|notes=}}
{{WAint|exit
|county=Skagit
|cspan=12
|location=none
|mile=218.61
|exit=218
|road=Starbird Road
|notes=}}
{{WAint|exit
|location=none
|mile=221.13
|exit=221
|road={{jct|state=WA|SR|534|dir1=east|city1=Lake McMurray}}
|notes=}}
{{WAint|exit
|location=none
|mile=224.00
|exit=224
|type=incomplete
|road=Old Highway&nbsp;99 South
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|location=Mount Vernon
|lspan=3
|mile=225.19
|exit=225
|road=Anderson Road
|notes=}}
{{WAint|exit
|mile=226.45
|exit=226
|road={{jct|state=WA|SR|536|dir1=west|name1=Kincaid Street}}
|notes=}}
{{WAint|exit
|mile=227.79
|exit=227
|road={{jct|state=WA|SR|538|dir1=east|name1=College Way}}
|notes=}}
{{WAint|exit
|location=Burlington
|lspan=3
|mile=228.93
|exit=229
|road=George Hopper Road
|notes=}}
{{WAint|exit
|mile=230.20
|exit=230
|road={{jct|state=WA|SR|20|city1=Burlington|city2=Anacortes}}
|notes=}}
{{WAint|exit
|mile=231.27
|exit=231
|road={{jct|state=WA|SR|11|dir1=north|name1=Chuckanut Drive|city1=Bow|city2=Edison|city3=Burlington}}
|notes=}}
{{WAint|exit
|location=none
|mile=232.89
|exit=232
|road=Cook Road&nbsp;– [[Sedro-Woolley, Washington|Sedro-Woolley]]
|notes=}}
{{WAint|exit
|location=none
|mile=236.45
|exit=236
|road=Bow Hill Road&nbsp;– [[Bow, Washington|Bow]], [[Edison, Washington|Edison]]
|notes=}}
{{WAint|exit
|location=none
|mile=240.99
|exit=240
|road=[[Alger, Washington|Alger]]
|notes=}}
{{WAint|exit
|county=Whatcom
|cspan=20
|location=none
|mile=242.92
|exit=242
|road=Nulle Road&nbsp;– [[Lake Samish|South Lake Samish]]
|notes=}}
{{WAint|exit
|location=none
|mile=246.30
|exit=246
|road=[[Lake Samish|North Lake Samish]]
|notes=}}
{{WAint|exit
|location=Bellingham
|lspan=8
|mile=250.79
|exit=250
|road={{jct|state=WA|SR|11|dir1=south|name1=Old Fairhaven Parkway, Chuckanut Drive|location1=[[Alaska Marine Highway]]|extra=ferry}}
|notes=}}
{{WAint|exit
|mile=252.14
|exit=252
|road=Samish Way&nbsp;– [[Western Washington University]]
|notes=}}
{{WAint|exit
|mile=253.03
|exit=253
|road=Lakeway Drive
|notes=}}
{{WAint|exit
|mile=253.85
|exit=254
|road=Iowa Street, Ohio Street, State Street
|notes=}}
{{WAint|exit
|mile=254.88
|exit=255
|road={{jct|state=WA|SR|542|dir1=east|name1=Sunset Drive|city1=Mt. Baker}}
|notes=}}
{{WAint|exit
|mile=256.27
|exit=256
|road={{jct|state=WA|SR|539|dir1=north|name1=Meridian Street|road|[[Bellis Fair Mall]]|city1=Lynden}}
|notes=Signed as exits&nbsp;256A (SR&nbsp;539) and 256B (Bellis Fair Mall Parkway) northbound}}
{{WAint|exit
|mile=257.04
|exit=257
|road=Northwest Avenue
|notes=}}
{{WAint|exit
|mile=257.72
|exit=258
|road={{jct|extra=airport}} Bakerview Road&nbsp;– [[Bellingham International Airport]]
|notes=}}
{{WAint|exit
|location=Ferndale
|lspan=4
|mile=260.19
|exit=260
|road=Slater Road&nbsp;– [[Lummi Island]]
|notes=}}
{{WAint|exit
|mile=262.63
|exit=262
|road=Main Street&nbsp;– [[Ferndale, Washington|Ferndale City Center]]
|notes=}}
{{WAint|exit
|mile=263.52
|exit=263
|road=Portal Way
|notes=}}
{{WAint|exit
|mile=266.04
|exit=266
|road={{jct|state=WA|SR|548|dir1=north|name1=Grandview Road|city1=Custer}}
|notes=}}
{{WAint|exit
|location=none
|mile=270.30
|exit=270
|road=[[Birch Bay, Washington|Birch Bay]], [[Lynden, Washington|Lynden]]
|notes=}}
{{WAint|exit
|location=Blaine
|lspan=5
|mile=274.23
|exit=274
|type=incomplete
|road=Peace Portal Drive&nbsp;– [[Semiahmoo, Washington|Semiahmoo]]
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=275.21
|exit=275
|type=incomplete
|road={{jct|state=BC|WA|543|dir1=north|BC|15|to2=yes|location1=[[Pacific Border Crossing]] (Truck Customs)}}
|notes=Northbound exit&nbsp;and southbound entrance}}
{{WAint|exit
|mile=276.26
|exit=276
|road={{jct|state=WA|SR|548|dir1=south|location1=[[Blaine, Washington|Blaine City Center]]|location2=[[Peace Arch State Park]]}}
|notes=}}
{{WAint|exit
|mile=276.62
|mspan=2
|place=[[Canada–United States border|Canada&nbsp;– United States border]] at [[Peace Arch Border Crossing]]
}}
{{Jctint|exit
|mile=none
|exit=—
|road={{jct|province=BC|Hwy|99|dir1=north|city1=Vancouver}}
|notes=Continuation into [[British Columbia]]
}}
{{jctbtm|exit|keys=concur,incomplete,hov,unbuilt}}

==References==
{{reflist}}

==External links==
{{Attached KML|display=title,inline}}
*{{commons-inline|Category:Interstate 5 in Washington (state)}}
*[https://www.angelfire.com/wa2/hwysofwastate/i005.html Interstate 5 at Highways of Washington State]
*[http://www.aaroads.com/guide.php?page=i0005wa Interstate 5 at AARoads]
*[https://wsdot.com/travel/real-time/alerts/road/005 Interstate 5 at WSDOT]

{{state detail page browse|type=I|route=5|state=Washington|statebefore=Oregon}}
{{3di|5}}
{{State highways in Washington related to I-5}}

{{DEFAULTSORT:I05 in Washington}}
[[Category:Interstate 5|*Washington]]
[[Category:Interstate Highways in Washington (state)|05]]
[[Category:U.S. Route 99|Interstate 05 in Washington]]
[[Category:Transportation in Clark County, Washington]]
[[Category:Transportation in Cowlitz County, Washington]]
[[Category:Transportation in Lewis County, Washington]]
[[Category:Transportation in Thurston County, Washington]]
[[Category:Transportation in Pierce County, Washington]]
[[Category:Transportation in King County, Washington]]
[[Category:Transportation in Snohomish County, Washington]]
[[Category:Transportation in Skagit County, Washington]]
[[Category:Transportation in Whatcom County, Washington]]
[[Category:Transportation in Seattle]]
[[Category:Roads with a reversible lane]]