View source for Interstate 526

{{short description|Highway in South Carolina}}
{{Use American English|date=April 2025}}
{{Use mdy dates|date=March 2015}}
{{Infobox road
|state=SC
|type=I
|route=526
|map={{maplink-road|from=Interstate 526.map}}
|map_custom=yes
|map_notes=I-526 highlighted in red; future section in blue; unbuilt future section in orange
|alternate_name=Mark Clark Expressway
|length_mi=19.56
|length_ref=<ref name="FHWA-Log">{{cite web |year=2018 |title=Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of December 31, 2018 |url=https://www.fhwa.dot.gov/planning/national_highway_system/interstate_highway_system/routefinder/table02.cfm |work=Route Log and Finder List |publisher=[[Federal Highway Administration]] |accessdate=January 22, 2022}}</ref><ref name="SCDOT GIS"/>
|counties=[[Charleston County, South Carolina|Charleston]], [[Berkeley County, South Carolina|Berkeley]]
|direction_a=West
|terminus_a={{Jct|state=SC|US|17|SC|7}} in [[Charleston, South Carolina|Charleston]]
|junction={{Jct|state=SC|I|26}} in [[North Charleston, South Carolina|North Charleston]]<br />{{Jct|state=SC|US|52|US|78}} in [[North Charleston, South Carolina|North Charleston]]
|direction_b=East
|terminus_b={{Jct|state=SC|US|17|BS|526|dab2=Mount Pleasant}} in [[Mount Pleasant, South Carolina|Mount Pleasant]]
|established=1989
|spur_type=I
|spur_of=26
|previous_type=SC
|previous_route=522
|next_type=SC
|next_route=527
}}
'''Interstate&nbsp;526''' ('''I-526''') is a {{convert|19.56|mi|km|adj=on}} [[List of auxiliary Interstate Highways|auxiliary route]] of [[Interstate 26 in South Carolina|I-26]], providing a partial beltway around [[Charleston, South Carolina|Charleston]], [[South Carolina]], in the [[United States]]. The route serves several purposes, firstly, as a [[Bypass (road)|bypass]] for through traffic on [[U.S. Route 17 in South Carolina|U.S. Route&nbsp;17]] (US&nbsp;17) to avoid downtown Charleston, and, secondly, for traffic on I-26 bound for the coastal towns located north and south of Charleston. The route is not yet complete, as the western terminus it is planned for the route to be extended an additional {{Convert|10|mi|km}}. After the eastern terminus, the roadway continues as a short [[business route]], known as Interstate&nbsp;526 Business (I-526 Bus.).

==Route description==
I-526 begins at an incomplete interchange with US&nbsp;17 (Savannah Highway) and [[South Carolina Highway 7]] (SC&nbsp;7, Sam Rittenberg Boulevard) in the [[West Ashley]] section of the city of Charleston, just north of the [[Stono River]]. The interchange includes a loop ramp from northbound US&nbsp;17, a ramp from southbound US&nbsp;17, and a half-[[diamond interchange]] with SC&nbsp;7. The four-lane freeway heads north past the [[Citadel Mall]] and meets [[South Carolina Highway 461|SC&nbsp;461]] at a [[partial cloverleaf]] interchange. SC&nbsp;461 heads west as Glenn McConnell Parkway and east as Paul Cantrell Boulevard; both directions lead to [[South Carolina Highway 61|SC&nbsp;61]] (Ashley River Road). I-526 crosses SC&nbsp;61 and uses the [[General William C. Westmoreland Bridge]] to cross the [[Ashley River (South Carolina)|Ashley River]] into the city of North Charleston. The freeway has diamond interchanges with Leeds Avenue and [[South Carolina Highway 642|SC&nbsp;642]] (Dorchester Road) and crosses over [[CSX Transportation|CSX]]'s [[Charleston Subdivision]].<ref name="Google Maps I-526"/>

I-526 continues through a connected pair of half-diamond interchanges with Montague Avenue and International Boulevard. Both streets lead to the [[North Charleston Coliseum]] and [[Charles Towne Square]]; the latter one is the access road for Charleston International Airport. The Interstate curves east and reaches its junction with I-26, which is a [[cloverleaf interchange]] except for a flyover ramp from eastbound I-526 to westbound I-26. I-526 crosses over [[Norfolk Southern Railway]]'s SC Line and has a partial cloverleaf interchange with Rivers Avenue, which carries [[U.S. Route 52 in South Carolina|US&nbsp;52]] and [[U.S. Route 78 in South Carolina|US&nbsp;78]]. The Interstate continues from its overpass of the U.S. Routes as a viaduct above wetlands along Filbin Creek. The viaduct crosses over the CSX rail line again and has a four-ramp partial cloverleaf interchange with Rhett Avenue and a half-diamond interchange with Virginia Avenue. The Rhett Avenue interchange includes a U-turn ramp that allows access from westbound I-526 to Virginia Avenue and from the avenue to eastbound I-526.<ref name="Google Maps I-526"/>

I-526 crosses the Cooper River on the high-level [[Don N. Holt Bridge]] and enters the Daniel Island section of the city of Charleston in [[Berkeley County, South Carolina|Berkeley County]]. The freeway has partial cloverleaf interchanges on either side of Beresford Creek with Clements Ferry Road and Seven Farms Drive/River Landing Drive. Both interchanges lead to [[Blackbaud Stadium]], home of the [[Charleston Battery]], and the [[Family Circle Tennis Center]], home of the [[Family Circle Cup]]. I-526 continues southeast across the [[Wando River]] on the [[James B. Edwards Bridge]] back into [[Charleston County, South Carolina|Charleston County]] and the town of [[Mount Pleasant, South Carolina|Mount Pleasant]]. The freeway has a partial cloverleaf interchange with Long Point Road and curves south at Hobcaw Creek. I-526 has a partial flyover interchange to and from US&nbsp;17 in the direction of [[Georgetown, South Carolina|Georgetown]] before the Interstate reaches its eastern terminus at a partial cloverleaf interchange with US&nbsp;17 (Johnnie Dodds Boulevard). The highway continues as I-526 Bus., a four-lane highway that follows Chuck Dawley Boulevard to [[South Carolina Highway 703|SC&nbsp;703]] in the center of Mount Pleasant.<ref name="Google Maps I-526"/>

All of I-526 is included as part of the [[National Highway System (United States)|National Highway System]], a system of roadways important to the nation's economy, defense, and mobility.<ref name="NHS Charleston">{{cite web|title=National Highway System: Charleston--North Charleston, SC|url=http://www.fhwa.dot.gov/planning/national_highway_system/nhs_maps/south_carolina/charleston_sc.pdf|archive-url=https://web.archive.org/web/20151017132129/http://www.fhwa.dot.gov/planning/national_highway_system/nhs_maps/south_carolina/charleston_sc.pdf|url-status=dead|archive-date=October 17, 2015|publisher=United States Department of Transportation|date=October 1, 2012|access-date=August 14, 2013}}</ref>

==History==
Planning of the freeway dates back to the 1960s; construction on the first section began in 1979. Opened in 1982 as an unnumbered freeway, it traversed from Ashley River Road ([[South Carolina Highway 61|SC&nbsp;61]]) to Leeds Avenue, crossing over the [[Ashley River (South Carolina)|Ashley River]].

In 1985, the freeway became [[South Carolina Highway 31|SC&nbsp;31]], connecting [[U.S. Route 17 in South Carolina|US&nbsp;17]]/[[South Carolina Highway 7|SC&nbsp;7]] to Dorchester Road ([[South Carolina Highway 642|SC&nbsp;642]]). By 1987, it extended to International Boulevard, providing access to the [[Charleston International Airport]].<ref>{{cite map |publisher= [[South Carolina Department of Transportation]] |url= http://digital.tcl.sc.edu/cdm/singleitem/collection/scrm/id/787/rec/5 |format= PDF |title= General Highway Map, Charleston County, South Carolina |cartography= SCDOT |year= 1987 |access-date= May 20, 2013}}</ref>

In 1989, the freeway was rechristened as I-526 after it connected with [[Interstate 26 in South Carolina|I-26]] (exit&nbsp;212). In 1992, I-526 was extended east over the [[Cooper River (South Carolina)|Cooper River]] to [[Daniel Island]], then over the [[Wando River]] to [[Mount Pleasant, South Carolina|Mount Pleasant]] and its current eastern terminus with [[U.S. Route 17 in South Carolina|US&nbsp;17]] and I-526 Bus.<ref>{{cite map |publisher= [[South Carolina Department of Transportation]] |url= http://digital.tcl.sc.edu/cdm/singleitem/collection/scrm/id/771/rec/2 |format= PDF |title= General Highway Map, Charleston County, South Carolina |cartography= SCDOT |year= 1996 |access-date= May 20, 2013}}</ref>

In 1993, the Robert B. Scarborough Bridge was opened, connecting downtown [[Charleston, South Carolina|Charleston]] with [[James Island (South Carolina)|James Island]]; it is signed as [[South Carolina Highway 30|SC&nbsp;30]]. Since 1993, several residents and groups in the area have fought against the completion of I-526, which will connect both James Island and [[Johns Island, South Carolina|Johns Island]].<ref>{{cite web |url= http://coastalconservationleague.org/projects/i-526-extension/ |title=I-526 Extension |publisher= Coastal Conservation League |date=July 28, 2010 |access-date=September 19, 2011}}</ref><ref>{{cite web|url=http://www.nix526.org |title=So Much to Lose For So Little Gain |publisher=Nix 526 |access-date=September 19, 2011}}</ref> {{citation needed span|Approximately {{convert|10|mi|km}} separate the eastern terminus of I-526's current extent from the eastern terminus of SC&nbsp;30. The mileage markers and exit numbers on both SC&nbsp;30 and I-526 are based on an eventual merging of the routes, with miles&nbsp;1 to 3 occurring on SC&nbsp;30 and miles&nbsp;10 to 30 used on the current I-526 route.|date=February 2024}}

==Future==
The proposed missing section of I-526 was the subject of an environmental study that was completed in early 2014.<ref>{{cite web|url=http://www.dot.state.sc.us/i526/ |title=SCDOT - I-526 - Welcome to the Mark Clark Expressway! |publisher=SCDOT |date=September 30, 2010 |access-date=May 20, 2013}}</ref> Various alternative routings and options are being reviewed, but the general plan is to extend south from [[U.S. Route 17 in South Carolina|US&nbsp;17]] to [[Johns Island, South Carolina|Johns Island]] and then east to [[James Island (South Carolina)|James Island]], where it will connect with [[South Carolina Highway 30|SC&nbsp;30]] (possibly renumbering it). Some alternatives shown include the possibility that it will be built in [[Limited-access road|expressway]] grade instead, falling short of being labeled an Interstate Highway.<ref>{{cite map |format=PDF|author= Staff |url= http://www.scdot.org/MCE/pdfs/RPA_Overview.pdf |title= RPA Overview |work= Mark Clark Expressway Environmental Impact Study |publisher= South Carolina Department of Transportation |access-date= May 20, 2013}}</ref>

Citing Charleston County's inability to provide funds to cover the project's increased cost, the State Transportation Infrastructure Bank (SIB) board voted on May&nbsp;26, 2016, to abandon the proposed extension of I-526 across James and Johns Islands.<ref>{{cite web|url=http://www.thestate.com/news/politics-government/politics-columns-blogs/the-buzz/article80057052.html|title=S.C. agency moves to walk away from Charleston's I-526 extension}}</ref>

In 2021, SCDOT revived the 526-extension project. As of May 2023, they are aiming to start construction by 2025.<ref>{{cite web|url=https://www.scdotmarkclark.com/the-latest |title=The Latest- Mark Clark Extension|publisher=South Carolina Department of Transportation|access-date=April 22, 2022}}</ref><ref>{{cite news |last1=Harris |first1=Anna |title=SCDOT breaks down the costs of the I-526 extension |url=https://www.live5news.com/2023/01/27/scdot-breaks-down-costs-i-526-extension/ |access-date=20 July 2023 |work=www.live5news.com |date=27 January 2023 |language=en}}</ref> In December 2023, the South Carolina Joint Bond Review Committee approved the state's Transportation Infrastructure Bank's action Tuesday afternoon of providing $75 million for preliminary costs in the project, which is dubbed the ''Mark Clark Extension Project''.<ref>{{cite news |last1=Johnson |first1=Emily |title=SC Committee approves $75 million toward I-526 extension, includes stipulation |url=https://www.live5news.com/2023/12/05/sc-committee-approves-75-million-toward-i-526-extension-includes-stipulation/ |access-date=10 March 2024 |work=www.live5news.com |date=5 December 2023 |language=en}}</ref>

On May 12th, 2025, the SIB voted once again to abandon the project, citing Charleston County's failure to pass a half-percent sales tax to help fund the project.<ref>{{cite news |last1=Slade |first1=David |title=The 526 Mark Clark Extension project is no more, officially killed by state officials Monday |url=https://www.postandcourier.com/news/mark-clark-extension-526-charleston-county-land/article_4197ad20-4dc7-44e6-82aa-eeebe133c16e.html |access-date=14 May 2025 |work=The Post and Courier |date=12 May 2024 |language=en}}</ref>

==Exit list==
{{jcttop|exit|length_ref=<ref name="SCDOT GIS"/>}}<!-- western terminus is officially at MP 10.00 -->
{{SCint|exit
|county=Charleston
|cspan=10
|location=Charleston
|lspan=2
|mile=10.00
|exit=10
|road={{jct|state=SC|US|17|SC|7|name1=Savannah Highway|name2=Sam Rittenburg Boulevard|location1=[[Savannah, Georgia|Savannah]]}}
|notes=Western terminus
}}
{{SCint|exit
|mile=11.39
|exit=11
|road={{jct|state=SC|SC|461|SC|61|to2=y|name1=Paul Cantrell Boulevard / Glenn McConnell Parkway|name2=Ashley River Road}}
|notes=Split into exits 11A (south) and 11B (north)
}}
{{jctbridge|exit
|location_special=[[Ashley River (South Carolina)|Ashley River]]
|bridge=[[General William C. Westmoreland Bridge]]
}}
{{SCint|exit
|location=North Charleston
|lspan=7
|mile=13.91
|exit=14
|road=Leeds Avenue
}}
{{SCint|exit
|mile=14.74
|exit=15
|road={{jct|state=SC|SC|642|name1=Dorchester Road|road|Paramount Drive}}
}}
{{SCint|exit
|mile=15.58
|exit=16
|road={{jct|extra=airport}} Montague Avenue / International Boulevard&nbsp;– [[Charleston International Airport]]
|notes=Split into exits 16A (Montague Avenue and International Boulevard) and 16B (Airport) eastbound
}}
{{SCint|exit
|mile=17.04
|exit=17
|road={{jct|state=SC|I|26|city1=Charleston|city2=Columbia}}
|notes=Split into exits 17A (east) and 17B (west) westbound
}}
{{SCint|exit
|mile=17.65
|exit=18
|road={{jct|state=SC|US|52|US|78|name2=Rivers Avenue}}
|notes=Split into exits 18A (east) and 18B (west)
}}
{{SCint|exit
|mile=19.09
|exit=19
|road=North Rhett Avenue
|notes=Includes direct U-turn ramp from westbound I-526 exit to eastbound I-526 entrance
}}
{{SCint|exit
|type=incomplete
|mile=19.39
|exit=20
|road=Virginia Avenue
|notes=Eastbound exit and westbound entrance; movements between Virginia Avenue and I-526 to and from Mount Pleasant are made using the exit 19 U-turn ramp
}}
{{jctbridge|exit
|river=[[Cooper River (South Carolina)|Cooper River]]
|bridge=[[Don N. Holt Bridge]]
}}
{{SCint|exit
|county=Berkeley
|cspan=2
|location=Charleston
|lspan=2
|mile=22.50
|exit=23
|road=Clements Ferry Road
|notes=Split into exits 23A (south) and 23B (north) eastbound
}}
{{SCint|exit
|mile=23.96
|exit=24
|road=River Landing Drive / Seven Farms Drive / Island Park Drive&nbsp;– [[Daniel Island]]
}}
{{jctbridge|exit
|river=[[Wando River]]
|bridge=[[James B. Edwards Bridge]]
}}
{{SCint|exit
|county=Charleston
|cspan=3
|location=Mount Pleasant
|lspan=3
|mile=27.46
|exit=28
|road=Long Point Road
}}
{{SCint|exit
|type=incomplete
|mile=28.69
|exit=29
|road={{jct|state=SC|US|17|dir1=north|city1=Georgetown}}
|notes=Eastbound exit and westbound entrance
}}
{{SCint|exit
|mile=29.56
|type=incomplete
|exit=30
|road={{jct|state=SC|US|17|name1=Johnnie Dodds Boulevard|BS|526|dab2=Mount Pleasant|dir2=east|name2=Chuck Dawley Boulevard|to3=y|SC|703|city1=Charleston}}
|notes=Eastern terminus; roadway continues as I-526 Bus.; no access from eastbound I-526 to northbound US&nbsp;17 or from southbound US&nbsp;17 to westbound I-526
}}
{{Jctbtm|exit|keys=incomplete}}

==Interstate 526 Business==
{{Infobox road small
|state=SC
|type=BS
|route=526
|location=[[Mount Pleasant, South Carolina]]
|formed=1992
|length_mi=1.570
|length_ref=<ref name="SCDOT RIS MP Bus">{{cite web |url=https://ris.scdot.org/LogMileReport.aspx?county=10&type=4&number=526&auxiliary=5&map=y |title=Highway Logmile Report |publisher=South Carolina Department of Transportation |access-date=December 14, 2020 }}</ref>
}}
'''Interstate&nbsp;526 Business''' ('''I-526 Bus.'''), per the South Carolina Department of Transportation '''South Carolina Highway 526 Spur''',<ref>{{cite map|title=Charleston Urban Area|url=https://info2.scdot.org//GISMapping/GISMapdl/Charleston_Metro_2018.pdf|sheet=24|publisher=South Carolina Department of Transportation|date=August 2020}}</ref> is a {{convert|1.57|mi|km|adj=on}} four-lane [[boulevard]]-grade [[business spur]] of I-526 along '''Chuck Dawley Boulevard''' between Johnnie Dodds Boulevard ([[U.S. Route 17 in South Carolina|US&nbsp;17]]) and Ben Sawyer Boulevard ([[South Carolina Highway 703|SC&nbsp;703]]).<ref name=google-pleasant>{{google maps |url=https://maps.google.com/maps?saddr=I-526BUS%2FInterstate+526+E&daddr=Chuck+Dawley+Blvd&hl=en&ll=32.805276,-79.849749&spn=0.030191,0.055747&sll=32.796185,-79.85919&sspn=0.015097,0.027874&geocode=FUuz9AEdLJc9-w%3BFd5n9AEdImc9-w&mra=dme&mrsp=1&sz=16&t=p&z=15 |title=Overview map of I-526 Bus. (Mount Pleasant) |link=no |access-date=May 19, 2013 }}</ref> <!-- The route was originally part of [[U.S. Route 17 Business (Mount Pleasant, South Carolina)|U.S. Route&nbsp;17 Business]] (US&nbsp;17 Bus.)/[[U.S. Route 701 Business (Mount Pleasant, South Carolina)|US&nbsp;701 Bus.]];{{cn|date=December 2020}} signed east–west, it has not changed since inception.{{cn|date=December 2020}} -->

I-526 Bus. is not part of the [[National Highway System (United States)|National Highway System]].<ref name="NHS Charleston"/>

{{Jcttop|state=SC|location=Mount Pleasant|county=Charleston|length_ref=<ref name="SCDOT RIS MP Bus"/>}}
{{SCint
|mile=0.000
|road={{Jct|state=SC|I|526|dir1=west|US|17|name2=Johnnie Dodds Boulevard|city1=North Charleston|city2=Charleston|city3=Georgetown|nolink1=y}}
|notes=Western terminus; continuation as I-526; former [[U.S. Route 701 in South Carolina|US&nbsp;701]]
}}
{{SCint
|mile=1.570
|road={{Jct|state=SC|SC|703|name1=Ben Sawyer Boulevard|city1=Charleston|city2=Sullivan's Island}}
|notes=Eastern terminus
}}
{{Jctbtm}}
{{Clear}}

==See also==
*{{Portal-inline|United States}}
*{{Portal-inline|U.S. roads}}
{{Clear}}

==References==
{{reflist|refs=

<ref name="SCDOT GIS">{{cite map|publisher=[[South Carolina Department of Transportation]]|title=Highways - Zipped Shapefile of roads maintained by SCDOT - Statewide|url=http://dbw.scdot.org/GISMapping/pdfs/GIS/Statewide_Highways_2012.zip|format=ESRI shapefile|year=2012|access-date=May 31, 2012}}{{Dead link|date=January 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

<ref name="Google Maps I-526">{{google maps|url=https://maps.google.com/maps?saddr=Unknown+road&daddr=I-526BUS%2FInterstate+526+E&hl=en&sll=32.792325,-80.027976&sspn=0.008821,0.021007&geocode=FV5S9AEd0886-w%3BFeqy9AEdIpc9-w&t=h&mra=ls&z=12|title=Interstate 526|access-date=May 21, 2013}}</ref>

<!-- uncomment after parameters are changed
<ref name="SCDOT County Maps">{{cite web|url=http://dbw.scdot.org/GISMapping/default.aspx|title=General County Highway Maps|publisher=South Carolina Department of Transportation|access-date=May 31, 2012}}
*[http://dbw.scdot.org/GISMapping/pdfs/County/Charleston_County.pdf Charleston County] (PDF)
</ref>
-->
}}

==External links==
{{Attached KML|display=title,inline}}
*{{commons category-inline}}
*[https://www.angelfire.com/sc3/scroads/i526.html Mapmikey's South Carolina Highways Page: I-526]

{{3di|26}}

[[Category:Auxiliary Interstate Highways|26-5]]
[[Category:Interstate Highways in South Carolina|26-5]]
[[Category:Interstate 26|526]]
[[Category:Beltways in the United States|526]]
[[Category:Transportation in Charleston, South Carolina|Interstate 26-5]]
[[Category:Transportation in North Charleston, South Carolina|Interstate 26-5]]
[[Category:Transportation in Charleston County, South Carolina]]
[[Category:Transportation in Berkeley County, South Carolina]]