View source for San Mateo County, California

{{short description|County in California, United States}}
{{distinguish|San Mateo, California}}
{{Use American English|date=June 2025}}
{{Use mdy dates|date=April 2024}}
{{Infobox settlement
| name               = San Mateo County
| other_name         = 
| settlement_type    = [[List of counties in California|County]]
<!-- Images and maps  ----------->
| image_skyline      =  {{multiple image
  | total_width        = 280
  | border             = infobox
  | perrow             = 1/2/2/1
  | caption_align      = center
  | image1             = Pacifica, California - aerial view (cropped).jpg
  | caption1           = [[Pacifica, California|Pacifica]] on the [[Coastal California|Californian Coast]]
  | image2             = San Mateo County History Museum (cropped).jpg
  | caption2           = [[Redwood City, California|Redwood City]]
  | image3             = Ritz Carlton HMB in the age of COVID (49812323307) (cropped).jpg
  | caption3           = [[Half Moon Bay, California|Half Moon Bay]]
  | image4             = Ano Nuevo State Park.JPG
  | caption4           = [[Año Nuevo State Park|Año Nuevo]]
  | image5             = Carolands Chateau (cropped2).jpg
  | caption5           = [[Hillsborough, California|Hillsborough]]
  | image6             = La Honda Road - panoramio (cropped).jpg
  | caption6           = [[La Honda, California|La Honda]]-[[San Gregorio, California|San Gregorio]]
  }}
| image_size         = 
| motto              = ''All of California in One County''
| image_flag         = 
| image_seal         = Seal of San Mateo County, California.svg
| seal_size          = 90px
| image_map          = {{Maplink|frame=yes|plain=yes|frame-width=250|frame-align=center|type=shape|fill=#ffffff|fill-opacity=0|stroke-width=3}}
| map_caption        = Interactive map of San Mateo County
| image_map1         = Map of California highlighting San Mateo County.svg
| mapsize1           = 200px
| map_caption1       = Location in [[California]]
| coordinates        = {{coord|37.44|-122.36|type:adm2nd_region:US-CA_source:UScensus1990|display=inline,title}}
| subdivision_type   = [[List of sovereign states|Country]]
| subdivision_name   = United States
| subdivision_type1  = [[U.S. state|State]]
| subdivision_name1  = California
| subdivision_type2  = [[List of regions of California|Region]]
| established_title  = [[Municipal corporation|Incorporated]]
| established_date   = April 19, 1856<ref>{{Cite GNIS|277305|San Mateo County|access-date=February 1, 2015}}</ref>
| leader_title       = 
| leader_name        = 
| named_for          = [[Matthew the Apostle|Saint Matthew]] (English translation)
| seat_type          = [[County seat]]<br />{{nobold|and largest city by area}}
| seat               = [[Redwood City, California|Redwood City]]
| seat1_type         = Largest city by population
| seat1              = [[San Mateo, California|San Mateo]]
| unit_pref          = US
| area_total_sq_mi   = 744
| area_land_sq_mi    = 448
| area_water_sq_mi   = 293
| elevation_max_footnotes = <ref>{{Cite web|url=http://www.peakbagger.com/peak.aspx?pid=1195|title=Long Ridge|publisher=Peakbagger.com|access-date=February 9, 2015}}</ref>
| elevation_max_ft   = 2603
| elevation_min_footnotes = 
| elevation_min_ft   = <!-- Government ----------->
| government_type    = [[Council–manager government|Council–CEO]]
| governing_body     = [[San Mateo County Board of Supervisors|Board of Supervisors]]
| leader_title1      = President<ref>{{Cite web|url=https://www.smcgov.org/district-5|title=District 5 &#124; County of San Mateo, CA|website=www.smcgov.org}}</ref>
| leader_name1       = David Canepa
| leader_title2      = Vice President<ref>{{Cite web|url=https://www.smcgov.org/district-2|title=District 2 &#124; County of San Mateo, CA|website=www.smcgov.org}}</ref>
| leader_name2       = Noelia Corzo
| leader_title3      = Board of Supervisors<ref>{{cite web | url=https://www.smcgov.org/bos | title=Board of Supervisors &#124; County of San Mateo, CA }}</ref>
| leader_name3       = {{Collapsible list
| title = Supervisors
| frame_style = border:none; padding:0;
| list_style  = text-align:left;
| 1  = [[Jackie Speier]]
| 2  = Noelia Corzo
| 3  = Ray Mueller
| 4  = Lisa Gauthier
| 5  = David Canepa
}}
| leader_title4      = County executive officer
| leader_name4       = Mike Callagy
<!-- Population ----------->| population_as_of   = [[2020 United States census|April 1, 2020]]
| population_footnotes = <ref name="QF">{{cite web|title=State & County QuickFacts|url=http://quickfacts.census.gov/qfd/states/06/06081.html|publisher=United States Census Bureau|access-date=April 6, 2016|archive-date=August 1, 2011|archive-url=https://web.archive.org/web/20110801001836/http://quickfacts.census.gov/qfd/states/06/06081.html|url-status=dead}}</ref>
| population_total   = 764442
| pop_est_as_of      = 
| pop_est_footnotes  = 
| population_est     = 
| population_density_sq_mi = 1704
<!-- GDP ----------->| demographics_type2 = GDP
| demographics2_footnotes = <ref name="bea.gov">{{cite web |url = https://fred.stlouisfed.org/series/GDPALL06081 |title = Gross Domestic Product: All Industries in San Mateo County, CA |website = fred.stlouisfed.org}}</ref>
| demographics2_title1 = Total
| demographics2_info1 = $202.488 billion (2023) 
<!-- Time zones ----------->| timezone           = [[Pacific Time Zone]]
| utc_offset         = -8
| timezone_DST       = [[Pacific Daylight Time]]
| utc_offset_DST     = -7
| postal_code_type   = <!--[[ZIP Code]]-->
| postal_code        = 
| area_code_type     = [[North American Numbering Plan|Area codes]]
| area_code          = [[Area codes 415 and 628|415/628]], [[Area code 650|650]]
| blank_name_sec1    = [[Federal Information Processing Standard|FIPS]] code
| blank_info_sec1    = 06-081
| blank1_name_sec1   = [[Geographic Names Information System|GNIS]] feature ID
| blank1_info_sec1   = {{GNIS 4|277305}}
| website            = {{Official URL}}
| blank_name_sec2    = Congressional districts
| blank_info_sec2    = [[California's 15th congressional district|15th]], [[California's 16th congressional district|16th]]
| footnotes          = 
}}

'''San Mateo County''',{{efn|({{IPAc-en|audio=En-us-san mateo.ogg|ˌ|s|æ|n|_|m|ə|ˈ|t|eɪ|.|oʊ}} {{respell|SAN|_|mə|TAY|oh}})}} officially the '''County of San Mateo''', is a [[county (United States)|county]] located in the [[U.S. state]] of [[California]]. As of the [[2020 United States census]], the population was 764,442.<ref>{{Cite web|title=San Mateo County, California|url=https://data.census.gov/cedsci/profile?g=0500000US06081|website=[[United States Census Bureau]]|accessdate=January 30, 2022}}</ref> [[Redwood City, California|Redwood City]] is the [[county seat]],<ref name="GR6">{{cite web|url=http://www.naco.org/Counties/Pages/FindACounty.aspx|access-date=June 7, 2011|title=Find a County|publisher=National Association of Counties}}</ref> the third-most populated city in the county after [[Daly City, California|Daly City]] and [[San Mateo, California|San Mateo]].

San Mateo County is included in the [[San Francisco–Oakland–Berkeley, CA MSA]] ([[metropolitan statistical area]]), [[Silicon Valley]], and is part of the [[San Francisco Bay Area]], the nine counties bordering [[San Francisco Bay]]. As of 2020, it has a median household income of $128,091, the [[List of highest-income counties in the United States|fourth-highest household income]] of any county in the nation behind [[Loudoun County, Virginia]], [[Falls Church, Virginia]], and [[Santa Clara County, California]].

The county covers most of the [[San Francisco Peninsula]]. The county is predominantly suburban and is home to many corporate campuses.

==History==
San Mateo County was formed in 1856 upon the division of San Francisco County, one of the state's 18 original counties established at California statehood in 1850. Until 1856, [[San Francisco]]'s city limits extended west to [[Divisadero Street]] and Castro Street, and south to 20th Street. In 1856, the California state government divided the county. A straight line was then drawn across the tip of the San Francisco Peninsula just north of [[San Bruno Mountain]]. Everything south of the line became the new San Mateo County while everything north of the line became the new consolidated [[San Francisco|City and County of San Francisco]].<ref>{{cite book |author=<!--no by-line.--> 
|title= Statutes of California and Digests of Measures
|url= https://books.google.com/books?id=4a83AAAAIAAJ&pg=PA145
|publisher= J. Winchester
|page=145 
|date=1856
}}</ref>
San Mateo County was officially organized on April 18, 1857, under a bill introduced by Senator [[Timothy Guy Phelps|T.G. Phelps]]. The 1857 bill defined the southern boundary of San Mateo County as following the south branch of [[San Francisquito Creek]] to its source in the [[Santa Cruz Mountains]] and thence due west to the Pacific Ocean, and named Redwood City as the county seat.<ref name=Alexander-Hamm>{{cite book |url=https://catalog.hathitrust.org/Record/011725171 |title=History of San Mateo County: from the earliest times with a description of its resources and advantages; and the biographies of its representative men |author1=Alexander, Philip W. |author2=Hamm, Charles P. |publisher=Burlingame Publishing Company |location=Burlingame, California |date=1916 |page=22 |access-date=August 5, 2016}}</ref> San Mateo County then annexed part of northern [[Santa Cruz County, California|Santa Cruz County]] in March 1868, including [[Pescadero, California|Pescadero]] and [[Pigeon Point Lighthouse|Pigeon Point]].<ref name="cagenealogy101.com">{{cite web|url=http://www.mapofus.org/california/ |title=California Maps |date=1856 |publisher=CA Genealogy |archive-url=https://web.archive.org/web/20130607090109/http://www.cagenealogy101.com/maps |archive-date=June 7, 2013 |url-status=live }}</ref><ref name=Alexander-Hamm />

Although the formation bill named Redwood City the county seat, a May 1856 election marked by "unblushing frauds perpetuated on an unorganized and wholly unprotected community by thugs and ballot stuffers from San Francisco" named Belmont the county seat.<ref name=AH-24>Alexander & Hamm (1916), p. 24.</ref> The election results were declared illegal and the county government was moved to Redwood City, with land being donated from the original Pulgas Grant for the county government on February 27, 1858.<ref name=AH-24 /> Redwood City's status as county seat was upheld in two successive elections in May 1861 and December 9, 1873, defeating San Mateo and Belmont.<ref name=AH-24 /> Another election in May 1874 named San Mateo the county seat, but the state supreme court overturned that election on February 24, 1875, and the county seat has remained at Redwood City ever since.<ref name=AH-24 />

San Mateo County bears the [[Spanish language|Spanish]] name for [[Matthew the Evangelist|Saint Matthew]]. As a place name, San Mateo appears as early as 1776 in the diaries of Anza and Font.<ref>{{Cite book|title=California Place Names|last=Gudde|first=Erwin G.|publisher=University Of California Press|year=2004|isbn=0-520-24217-3|edition=Fourth|pages=341}}</ref> Several local geographic features were also designated San Mateo on early maps including variously: a settlement, an [[Arroyo (watercourse)|arroyo]], a headland jutting into the Pacific ([[Montara, California|Point Montara]]), and a large land holding ([[Rancho San Mateo]]). Until about 1850, the name appeared as ''San Matheo''.

===Japanese Americans in San Mateo===
The Japanese first arrived in San Mateo County and were part of a group guided by Ambassador Tomomi Iwakura in 1872.<ref>{{Cite book|title=Building A Community: The story of Japanese Americans in San Mateo County|last1=Yamada|first1=Gayle K.|last2=Fukami|first2=Dianne|publisher=AACP, Inc|year=2003|isbn=0-934609-10-1|pages=1}}</ref> A number of male Japanese students came to San Mateo to learn English and many other helpful skills to bring back to Japan.<ref name=":0">{{Cite book|title=Building A Community: The story of Japanese Americans in San Mateo County|last1=Yamada|first1=Gayle K.|last2=Fukami|first2=Dianne|publisher=AACP, Inc|year=2003|isbn=0-934609-10-1|pages=2–3}}</ref> These students were also some of the first Japanese to join American students in the Belmont School for Boys. These students had to work for their housing and food before classes and in the evenings.<ref name=":0" /> Many of the first Japanese immigrants were able to find jobs as gardeners and landscapers in San Mateo. Most of them had a good educational background from their homelands, but their lack of knowledge of the English language made it difficult for them to find other jobs in the beginning.<ref>{{Cite book|title=Building a Community: The Story of Japanese Americans in San Mateo County|last1=Yamada|first1=Gayle K.|last2=Fukami|first2=Dianne|publisher=AACP, Inc|year=2003|isbn=0-934609-10-1|pages=14}}</ref>

==Geography==
According to the [[U.S. Census Bureau]], the county has a total area of {{convert|741|sqmi}}, of which {{convert|448|sqmi}} is land and {{convert|293|sqmi}} (40%) is water.<ref name="GR1">{{cite web|url=http://www2.census.gov/geo/docs/maps-data/data/gazetteer/counties_list_06.txt|publisher=United States Census Bureau|access-date=October 4, 2015|date=August 22, 2012|title=2010 Census Gazetteer Files}}</ref> It is the third-smallest county in California by land area. A number of bayside watercourses drain the eastern part of the county including [[San Bruno Creek]] and [[Colma Creek]]. Streams draining the western county include [[Frenchmans Creek, California|Frenchmans Creek]], [[Pilarcitos Creek]], [[Naples Creek]], [[Arroyo de en Medio]], and [[Denniston Creek]]. These streams originate along the northern spur of the [[Santa Cruz Mountains]] that run through the county. The northern and eastern parts of the county are very heavy densely populated with largely urban and suburban areas, with many of its cities as edge-cities for the Bay Area, while the deep south and the west-central parts of the county are less densely populated with more rural environment and coastal beaches areas.
[[File:Portola Redwoods State Park in March 2020.jpg|thumb|left|The Santa Cruz Mountains cross through San Mateo County. In comparison to the rest of the county, the area is quite rural and forested.]]

===Features===
San Mateo County straddles the [[San Francisco Peninsula]], with the [[Santa Cruz Mountains]] running its entire length. The county encompasses a variety of habitats, including [[estuarine]], marine, oak woodland, redwood forest, coastal scrub and oak savannah. There are numerous species of [[wildlife]] present, especially along the [[San Francisco Bay]] estuarine shoreline, [[San Bruno Mountain]], [[Fitzgerald Marine Reserve]] and the forests on the Montara Mountain block. Several creeks discharge to the San Francisco Bay, including [[San Mateo Creek (San Francisco Bay Area)|San Mateo Creek]] and Laurel Creek, and several coastal streams discharge to the [[Pacific Ocean]], such as [[Frenchmans Creek (California)|Frenchmans Creek]] and [[San Vicente Creek (San Mateo County)|San Vicente Creek]].

[[Año Nuevo State Marine Conservation Area]] and [[Greyhound Rock State Marine Conservation Area]] are two adjoining [[marine protected area]]s off the coast of San Mateo County. Like underwater parks, these marine protected areas help conserve ocean wildlife and marine ecosystems.

===Flora and fauna===
The county is home to several [[endangered species]] including the [[San Francisco garter snake]] and the [[San Bruno elfin butterfly]], both of which are endemic to San Mateo County. The endangered [[Ridgway's Rail]] is also found on the shores of San Francisco Bay, in the cities of [[Belmont, California|Belmont]] and [[San Mateo, California|San Mateo]]. The endangered wildflower [[Hickman's potentilla]] is found near the Pacific Ocean on the lower slopes of [[Montara Mountain]]. The endangered wildflowers [[White-rayed pentachaeta]], ''[[Pentachaeta bellidiflora]]'', [[San Mateo Woolly Sunflower]], ''[[Eriophyllum latilobum]]'', [[Marin Dwarf Flax]], ''[[Hesperolinon congestum]]'' and the [[San Mateo Thornmint]], ''[[Acanthomintha duttonii]]'', are found in the vicinity of the [[Crystal Springs Reservoir]].

In May 2014, a [[California condor]] was spotted near [[Pescadero, California|Pescadero]], a coastal community south of San Francisco<ref name=Timesherald_1>{{cite web| author=P. Rogers| date=June 14, 2014| title=First California condor spotted in San Mateo County since 1904| url=http://www.timesheraldonline.com/breaking_news/ci_25964337/first-california-condor-spotted-san-mateo-county-since| publisher=[[Vallejo Times Herald]]| access-date=August 28, 2014| archive-url=https://web.archive.org/web/20140903042237/http://www.timesheraldonline.com/breaking_news/ci_25964337/first-california-condor-spotted-san-mateo-county-since| archive-date=September 3, 2014| url-status=dead| df=dmy-all}}</ref>—it was the first California condor spotted in San Mateo County since 1904.<ref name=Timesherald_1/> The condor, tagged with the number "597", and also known as "Lupine", is one of 439 condors living in the wild or captivity in California, Baja California and Arizona.<ref name=Timesherald_1/><ref>{{cite web| title=California Condor Recovery Program (monthly status report)| date=June 30, 2014| url=https://www.nps.gov/pinn/naturescience/upload/Condor-Program-Monthly-Status-Report-2014-6-30-One-Page.pdf| archive-url=https://web.archive.org/web/20140903130425/http://www.nps.gov/pinn/naturescience/upload/Condor-Program-Monthly-Status-Report-2014-6-30-One-Page.pdf| url-status=dead| archive-date=September 3, 2014| publisher=National Park Service| access-date=August 31, 2014}}</ref> The three-year-old female flew more than {{convert|100|mi|km}} north from [[Pinnacles National Park]], in San Benito County, on May 30, and landed on a private, forested property near Pescadero, on the San Mateo County Coast, where it was photographed by a motion-activated wildlife camera.<ref name=Timesherald_1/> Harold Heath, professor emeritus, of [[Stanford University]] was responsible for the 1904 sighting, {{convert|1|mi|km}} west of the university campus.<ref name=Timesherald_1/><ref>{{cite web| title=Memorial Resolution Harold Heath (1868 – 1951)| year=1951| url=http://historicalsociety.stanford.edu/pdfmem/HeathH.pdf| publisher=Historical Society Stanford| access-date=August 30, 2014| archive-url=https://web.archive.org/web/20140903203733/http://historicalsociety.stanford.edu/pdfmem/HeathH.pdf| archive-date=September 3, 2014| url-status=dead| df=dmy-all}}</ref>

[[Puma concolor|Pumas]] (''Puma concolor''), also known as cougars or mountain lions, roam the county.<ref>{{Cite news|url=https://abc7news.com/5540036/|title=Mountain lion dies after being hit by car on Highway 280 in San Mateo County|date=September 15, 2019|work=ABC7 San Francisco|language=en|access-date=September 16, 2019}}</ref>

[[Tule elk]] (''Cervus canadensis nannodes'') were native to San Mateo County and among the "favored foods" of the [[Ohlone people]] based on ethnohistoric and archeological evidence there.<ref>{{cite journal |title=Contributions to the Archaeology of San Mateo County. I: Introduction, Prior Archaeological Work in the San Francisco Bay Region |author1=Michael J. Moratto |author2=Balbir Singh |year=1971 |journal=San Francisco State College Treganza Anthropology Museum Papers |volume=8 |pages=1–8 |url=https://searchworks.stanford.edu/view/6803254 |access-date=March 24, 2020}}</ref> The discovery of two elk specimens made news in 1962, one a royal elk (royal elk bulls have six [[tine (structural)|tines]] per antler) from a peat bog excavated in Pacifica's historic Laguna Alta, and now in the [[Museum of Vertebrate Zoology]] collection.<ref>{{cite web |title=Royal Elk Fossil Found in San Mateo County, May 1962 |author=Norton Pearl |publisher=San Mateo County Historical Association |date=May 1, 1962 |url=https://historysmc.pastperfectonline.com/photo/D86EC528-CB09-47F0-9F91-747594556178 |access-date=March 24, 2020 }}</ref><ref>{{cite web |title=Mammal Collection, Museum of Vertebrate Zoology at Berkeley |url=http://arctos.database.museum/SpecimenResults.cfm |access-date=March 24, 2020}}</ref> These may date from the time of Spanish settlement.<ref>{{cite journal |title=Deposit on the San Francisco Peninsula |author=Dale R. McCullough |journal=Journal of Mammalogy |volume=46 |number=2 |date=May 1, 1965 |pages=347–348 |doi=10.2307/1377873 |jstor=1377873 |url=https://academic.oup.com/jmammal/article-abstract/46/2/347/853423 |access-date=March 24, 2020 |url-access=subscription }}</ref> Laguna Alta lay just south of the Interstate 280 and Skyline Boulevard intersection, east of Mussel Rock.<ref>{{cite web |title=Creek & Watershed Map of Daly City and Vicinity |author1=Robert W. Givler |author2=Janet M. Sowers |publisher=Oakland Museum |year=2007 |url=http://explore.museumca.org/creeks/WholeMaps/11_Daly%20City%20Creek%20Map.pdf}}</ref> The [[California Academy of Sciences]] also has an elk skull fragment collected one mile inland from the mouth of [[Purisima Creek (San Mateo County)|Purisima Creek]] in 1951.<ref>{{cite web |title=Cervus elaphus nannodes |url=http://researcharchive.calacademy.org/research/bmammals/MamColl/index.asp?xAction=getrec&close=true&CollectionObjectID=148981 |access-date=April 7, 2020 }}</ref> Additional coastal elk remains dating from the Middle and Late Periods in Northern California were found in at least five more late [[Holocene]] archeological sites in San Mateo County: SMA-115 ([[Montara State Beach]] site), SMA-118 ([[Bean Hollow State Beach]] site), SMA-244 ([[Butano State Park|Butano Ridge]] site), SMA-97 ([[Año Nuevo State Park|Año Nuevo]] Creek site) and SMA-218 (Año Nuevo State Reserve site).<ref>{{cite thesis |title=Prehistoric native American adaptations along the central California coast of San Mateo and Santa Cruz counties |author=Mark Gerald Hylkema |date=1991 |publisher=San Jose State University |url=https://scholarworks.sjsu.edu/etd_theses/131/ |access-date=March 24, 2020 }}</ref> On the eastern side of the [[San Francisco Peninsula]], elk remains were also unearthed at multiple archaeological sites along [[San Francisquito Creek]].<ref>{{cite journal |title=Sites and Site Clusters: Middle Period Archaeology of the San Francisquito Drainage |author=Barbara Bocek |year=1988 |journal=Society of California Archaeology Proceedings |volume=1 |pages=299–309 |url=https://scahome.org/download/proceedings/Proceedings.01Bocek.pdf |access-date=March 25, 2020 |archive-date=March 26, 2020 |archive-url=https://web.archive.org/web/20200326060209/https://scahome.org/download/proceedings/Proceedings.01Bocek.pdf |url-status=dead }}</ref><ref>{{cite journal |title=Subsistence, Settlement and Tribelet Territories on the Eastern San Francisco Peninsula |author=Barbara Bocek |year=1992 |journal=Society of California Archaeology Proceedings |volume=5 |pages=269–297 |url=https://scahome.org/publications/proceedings/Proceedings.05Bocek.pdf |access-date=March 25, 2020 }}</ref>

===National protected areas===
* [[Don Edwards San Francisco Bay National Wildlife Refuge]] (part)
* [[Golden Gate National Recreation Area]] (part)

===Marine protected area===
* [[Montara State Marine Reserve & Pillar Point State Marine Conservation Area]]

===County parks===
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 |fullscreen-option=1
 |caption=San Mateo County Parks&nbsp;<small>{{flatlist|
* {{color box|#282|Parks and open spaces|#fff|border=silver}}
* {{color box|#f22|Trails|#fff|border=silver}} 
* {{color box|#22f|Historic sites|border=silver}} }}</small>
}}
The County of San Mateo Parks Department operates 22 parks, trails, and historic sites spread throughout the county; the first, [[Memorial Park (San Mateo County, California)|Memorial Park]], was dedicated on July 4, 1924.<ref name=Svanevik-Burgett/>{{rp|12}} The County Superintendent of Schools, Roy Cloud, had visited a one-room schoolhouse in Harrison Canyon as part of his duties; at the time, it was thickly forested with old-growth redwoods and he was alarmed when he learned they were scheduled to be logged. He petitioned the County Board of Supervisors to purchase the land instead.<ref name=Svanevik-Burgett/>{{rp|9–11}} The Recreation Commission was not created until 1932, and the park was improved as part of the [[Works Progress Administration]] efforts starting in 1935.<ref name=Svanevik-Burgett/>{{rp|15}}
{|class="wikitable sortable" style="font-size:90%;text-align:center;"
|+San Mateo County Parks<ref name=Svanevik-Burgett>{{cite book |url=https://archive.org/details/sanmateocountypa00svan/ |url-access=registration |title=San Mateo County Parks: A remarkable story of extraordinary places and the people who built them |author1=Svanevik, Michael |author2=Burgett, Shirley |date=2001 |publisher=San Mateo County Parks and Recreation Foundation |location=San Mateo County, California |isbn=1-881529-67-3 |access-date=August 11, 2023}}</ref><ref>{{cite web |url=https://parks.smcgov.org/sites/parks.smcgov.org/files/documents/files/SMCParksGeneralBrochure-Nov2018-FINAL-web-formatted.pdf |title=San Mateo County Parks |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! No. !! Name !! class="unsortable" | Image !! Est. !! Size !! City !! class="unsortable" | Ref.
|-
! style="background:#282;color:#fff;font-size:150%;" | 1
! Coyote Point<small>{{flatlist|
*Marina
*[[Coyote Point Park|Recreation Area]]}}</small>
| [[File:Zeppelin-ride-020100925-130 (5028699547).jpg|100px]]
| 1963 || {{convert|149|+|538|acre|abbr=on|disp=br}}{{efn|149 acres of land, 538 acres underwater}}
| [[San Mateo, California|San Mateo]]/[[Burlingame, California|Burlingame]]
| <ref name="Coyote Point Recreation Area">{{cite web |url=https://parks.smcgov.org/coyote-point-recreation-area |title=Coyote Point Recreation Area |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref><ref name="Coyote Point Marina">{{cite web |url=https://parks.smcgov.org/coyote-point-marina |title=Coyote Point Marina |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#f22;color:#fff;font-size:150%;" | 2
! [[Crystal Springs Regional Trail|Crystal Springs]]<small>{{flatlist|
*[[San Andreas Trail|San Andreas]]
*[[Sawyer Camp Trail|Sawyer Camp]]
*[[Crystal Springs Trail|Crystal Springs]]}}</small>
| [[File:Lake San Andreas - Sawyer Camp Trail (15916868610).jpg|100px]]
|  || {{convert|17.5|mi|abbr=on|disp=br}}
| [[Burlingame, California|Burlingame]]
| <ref>{{cite web |url=https://parks.smcgov.org/crystal-springs-regional-trail |title=Crystal Springs Regional Trail |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#f22;color:#fff;font-size:150%;" | 3
! [[Devil's Slide Trail|Devil's Slide]]
| [[File:Devil's Slide Trail, which used to be an unstable part of California Highway 1 until they built bypass tunnels and turned it into a nature reserve. (26033922316).jpg|100px]]
|  || {{convert|1.3|mi|abbr=on|disp=br}}
| [[Pacifica, California|Pacifica]]/[[Montara, California|Montara]]
| <ref>{{cite web |url=https://parks.smcgov.org/devils-slide-trail |title=Devil's Slide Trail |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 4
! [[Edgewood Park & Natural Preserve|Edgewood]]
| [[File:Monday Night Birding (14177890134).jpg|100px]]
| 1980 || {{convert|467|acre|abbr=on|disp=br}}
| [[Redwood City, California|Redwood City]]
| <ref>{{cite web |url=https://parks.smcgov.org/edgewood-park-natural-preserve |title=Edgewood Park & Natural Preserve |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 5
! [[Fitzgerald Marine Reserve|Fitzgerald]]{{efn|Wholly contained within the [[Montara State Marine Reserve]]}}
| [[File:JV Fitzgerald Marine Reserve 04 (11013086134).jpg|100px]]
| 1969 || 
| [[Moss Beach, California|Moss Beach]]
| <ref>{{cite web |url=https://parks.smcgov.org/fitzgerald-marine-reserve |title=Fitzgerald Marine Reserve |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref><ref name="Coyote Point Marina"/>
|-
! style="background:#282;color:#fff;font-size:150%;" | 6
! [[Flood Park|Flood]]
|
|  || {{convert|21|acre|abbr=on|disp=br}}
| [[Menlo Park, California|Menlo Park]]
| <ref>{{cite web |url=https://parks.smcgov.org/flood-park |title=Flood Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 7
! [[Friendship Park (San Mateo County, California)|Friendship]]
|
|  || <{{convert|1|acre|abbr=on|disp=br}}
| [[Redwood City, California|Redwood City]]
| <ref>{{cite web |url=https://parks.smcgov.org/friendship-park |title=Friendship Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 8
! [[Huddart Park|Huddart]]
| [[File:Huddart park to Crystal Spring trail (2).jpg|100px]]
| 1948 || {{convert|974|acre|abbr=on|disp=br}}
| [[Woodside, California|Woodside]]
| <ref>{{cite web |url=https://parks.smcgov.org/huddart-park |title=Huddart Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 9
! [[Junipero Serra County Park|Junipero Serra]]
| [[File:Junipero Serra County Park 01 (7387783278).jpg|100px]]
| 1960 || {{convert|103|acre|abbr=on|disp=br}}
| [[San Bruno, California|San Bruno]]
| <ref>{{cite web |url=https://parks.smcgov.org/junipero-serra-park |title=Junipero Serra Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 10
! [[Memorial Park (San Mateo County, California)|Memorial]]
| [[File:Huckleberry Flat picnic area (3172631077).jpg|100px]]
| 1924 || {{convert|673|acre|abbr=on|disp=br}}
| [[Loma Mar, California|Loma Mar]]
| <ref>{{cite web |url=https://parks.smcgov.org/memorial-park |title=Memorial Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 11
! [[Mirada Surf]]
|
|  || {{convert|15|+|34|acre|abbr=on|disp=br}}{{efn|Divided by [[California State Route 1|State Route 1]] into the 15-acre Mirada Surf West and 34-acre East.}}
| [[El Granada, California|El Granada]]
| <ref name="Coyote Point Recreation Area"/><ref name="Coyote Point Marina"/>
|-
! style="background:#282;color:#fff;font-size:150%;" | 12
! [[Moss Beach Park|Moss Beach]]
|
| 2014 || {{convert|467|acre|abbr=on|disp=br}}
| [[Moss Beach, California|Moss Beach]]
| <ref name="Coyote Point Recreation Area"/><ref name="Coyote Point Marina"/>
|-
! style="background:#282;color:#fff;font-size:150%;" | 13
! [[Pescadero Creek County Park|Pescadero Creek]]
| [[File:Entering the Park (5365626915).jpg|100px]]
| 1968 || {{convert|8020|acre|abbr=on|disp=br}}
| [[Loma Mar, California|Loma Mar]]
| <ref>{{cite web |url=https://parks.smcgov.org/pescadero-creek-park |title=Pescadero Creek Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 14
! [[Pillar Point Bluff|Pillar Point]]
| [[File:Great Blue Heron at Pillar Point Bluffs.jpg|100px]]
| 2011|| {{convert|220|acre|abbr=on|disp=br}}
| [[Moss Beach, California|Moss Beach]]
| <ref>{{cite web |url=https://parks.smcgov.org/pillar-point-bluff |title=Pillar Point Bluff |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 15
! [[Quarry Park (San Mateo County, California)|Quarry]]
|
|  || {{convert|517|acre|abbr=on|disp=br}}
| [[El Granada, California|El Granada]]
| <ref>{{cite web |url=https://parks.smcgov.org/quarry-park |title=Quarry Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 16
! [[Sam McDonald County Park|Sam McDonald]]
| [[File:Sam McDonald County Park (16121518351).jpg|100px]]
| 1970 || {{convert|850|acre|abbr=on|disp=br}}
| [[Loma Mar, California|Loma Mar]]
| <ref>{{cite web |url=https://parks.smcgov.org/sam-mcdonald-park |title=Sam McDonald Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 17
! [[San Bruno Mountain State & County Park|San Bruno Mountain]]
| [[File:Aerial view of San Bruno Mountain.jpg|100px]]
| 1978 || {{convert|2416|acre|abbr=on|disp=br}}
| [[Brisbane, California|Brisbane]]
| <ref>{{cite web |url=https://parks.smcgov.org/san-bruno-mountain-state-county-park |title=San Bruno Mountain State & County Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 18
! [[San Pedro Valley County Park|San Pedro Valley]]
| [[File:San Pedro Valley Park, Pacifica.jpg|100px]]
| 1970s || {{convert|1052|acre|abbr=on|disp=br}}
| [[Pacifica, California|Pacifica]]
| <ref>{{cite web |url=https://parks.smcgov.org/san-pedro-valley-park |title=San Pedro Valley Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#22f;color:#fff;font-size:150%;" | 19
! [[Sanchez Adobe]]
| [[File:Sánchez Adobe exterior 2.JPG|100px]]
| 1953 || {{convert|5|acre|abbr=on|disp=br}}
| [[Pacifica, California|Pacifica]]
| <ref>{{cite web |url=https://parks.smcgov.org/sanchez-adobe |title=Sanchez Adobe |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 20
! [[Tunitas Creek Beach]]
| [[File:Tuitas Beach and Ocean Shore Railroad.jpg|100px]]
|  || 
| [[Half Moon Bay, California|Half Moon Bay]]
| <ref>{{cite web |url=https://parks.smcgov.org/tunitas-creek-beach |title=Tunitas Creek Beach |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#22f;color:#fff;font-size:150%;" | 21
! [[Woodside Store]]
| [[File:Woodside store.jpg|100px]]
| 1940 || —
| [[Woodside, California|Woodside]]
| <ref>{{cite web |url=https://parks.smcgov.org/woodside-store |title=Woodside Store |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|-
! style="background:#282;color:#fff;font-size:150%;" | 22
! [[Wunderlich County Park|Wunderlich]]
| [[File:Meadow Trail Wunderlich Park.jpg|100px]]
| 1974 || {{convert|942|acre|abbr=on|disp=br}}
| [[Woodside, California|Woodside]]
| <ref>{{cite web |url=https://parks.smcgov.org/wunderlich-park |title=Wunderlich Park |publisher=Parks Department, County of San Mateo |access-date=December 27, 2019}}</ref>
|}
;Notes
{{notelist}}

Prior to the rebuilding of the [[San Mateo Bridge]] that began in 1996, the county had also operated Werder Pier for fishermen; it had been the western segment of the original 1929 [[vertical-lift bridge]].

In addition to the county-operated parks, San Mateo County voters created the [[Midpeninsula Regional Open Space District]] in 1972, administered by the [[Peninsula Open Space Trust]], which owns several protected spaces within San Mateo County (as well as within Santa Clara and Santa Cruz counties). San Mateo County protected spaces administered by POST include:<ref>{{cite web |url=https://www.openspace.org/sites/default/files/district_map.pdf |title=Welcome to the Midpeninsula Regional Open Space District |publisher=Peninsula Opens Space Trust |access-date=December 27, 2019}}</ref>
{{div col|colwidth=22em}}
* Coal Creek Open Space Preserve
* [[El Corte de Madera Creek]]
* [[La Honda Creek Open Space Preserve]]
* [[Long Ridge Open Space Preserve]] (partially within Santa Clara County)
* [[Los Trancos Open Space Preserve]] (partially within Santa Clara County)
* [[Pulgas Ridge Open Space Preserve]]
* [[Purisima Creek Redwoods Open Space Preserve]]
* Ravenswood Open Space Preserve
* [[Russian Ridge Open Space Preserve]]
* Skyline Ridge Open Space Preserve
* Teague Hill Open Space Preserve
* [[Thornewood Open Space Preserve]]
* [[Windy Hill Open Space Preserve]]
{{div col end}}

===State parks===
{{div col|colwidth=22em}}
* [[Año Nuevo State Park]]
* [[Butano State Park]]
* Castle Rock State Park
* Heritage Grove
* [[Portola Redwoods State Park]]
* Quarry Park
* Burleigh H. Murray Ranch
* Pigeon Point Light Station Historic State Park
* Point Montara Light Station State Park
* [[San Bruno Mountain State Park]]
{{div col end}}

===State beaches===
{{div col|colwidth=22em}}
* Año Nuevo State Reserve
* Bean Hollow State Beach
* Big Basin State Beach
* Gray Whale Cove State Beach
* [[Half Moon Bay State Beach]]
* [[Montara State Beach]]
* [[Pacifica State Beach]]
* Pebble Beach
* [[Pescadero State Beach]]
* Pomponio State Beach
* [[San Gregorio State Beach]]
* Thornton State Beach
{{div col end}}

==Demographics==
{{US Census population
| 1860 = 3214
| 1870 = 6635
| 1880 = 8669
| 1890 = 10087
| 1900 = 12094
| 1910 = 26585
| 1920 = 36781
| 1930 = 77405
| 1940 = 111782
| 1950 = 235659
| 1960 = 444387
| 1970 = 556234
| 1980 = 587329
| 1990 = 649623
| 2000 = 707161
| 2010 = 718451
| 2020 = 764442
|estyear=2024
|estimate=742893
|estref=<ref name="USCensusEst2024">{{cite web|url=https://www.census.gov/programs-surveys/popest/data/tables.html|title=Annual Estimates of the Resident Population for Counties: April 1, 2020 to July 1, 2024|publisher=United States Census Bureau|access-date=May 10, 2025}}</ref>
| align-fn = center
| footnote = U.S. Decennial Census<ref name="DecennialCensus">{{cite web|url=https://www.census.gov/programs-surveys/decennial-census/decade.html|title=Decennial Census by Decade|publisher=[[US Census Bureau]]|access-date=}}</ref><br />1790–1960<ref>{{cite web|url=http://mapserver.lib.virginia.edu|title=Historical Census Browser|publisher=University of Virginia Library|access-date=October 4, 2015}}</ref> 1900–1990<ref>{{cite web|url=https://www.census.gov/population/cencounts/ca190090.txt|title=Population of Counties by Decennial Census: 1900 to 1990|publisher=United States Census Bureau|editor-last=Forstall|editor-first=Richard L.|date=March 27, 1995|access-date=October 4, 2015}}</ref><br />1990–2000<ref>{{cite web|url=https://www.census.gov/population/www/cen2000/briefs/phc-t4/tables/tab02.pdf|title=Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000|publisher=United States Census Bureau|date=April 2, 2001|access-date=October 4, 2015}}</ref> 2010<ref name=2010CensusP2/> 2020<ref name=2020CensusP2/>
| align = right
}}

===2020 census===
{| class="wikitable sortable" style="text-align:center;"
|+'''San Mateo County, California – Racial and ethnic composition'''<br><small>{{nobold|''Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.''}}</small>
!Race / Ethnicity <small>(''NH = Non-Hispanic'')</small>
!Pop 1980<ref>{{Cite web |title=California: 1980, General Social and Economic Characteristics, Part 1 - Table 59: Persons by Race, Hispanic Origin, and Sex|website=[[United States Census Bureau]]|url=https://www2.census.gov/prod2/decennial/documents/1980a_caCs1-01.pdf|access-date=}}</ref>
!Pop 1990<ref>{{Cite web |title=California: 1990, Part 1 - Table 5: Race and Hispanic Origin|website=[[United States Census Bureau]]|url=https://www2.census.gov/library/publications/decennial/1990/cp-1/cp-1-6-1.pdf |access-date=July 14, 2024}}</ref>
!Pop 2000<ref name=2000CensusP004>{{Cite web|title=P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – San Mateo County, California|url=https://data.census.gov/table?g=050XX00US06081&tid=DECENNIALSF12000.P004|website=[[United States Census Bureau]] |access-date= }}</ref>
!Pop 2010<ref name=2010CensusP2>{{Cite web|title=P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2010: DEC Redistricting Data (PL 94-171) – San Mateo County, California|url=https://data.census.gov/cedsci/table?q=p2&g=050XX00US06081&tid=DECENNIALPL2010.P2|website=[[United States Census Bureau]] |access-date= }}</ref>
!style="background-color: #ffffb3;" | Pop 2020<ref name=2020CensusP2>{{Cite web|title=P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2020: DEC Redistricting Data (PL 94-171) – San Mateo County, California|url=https://data.census.gov/cedsci/table?q=p2&g=050XX00US06081&tid=DECENNIALPL2020.P2|website=[[United States Census Bureau]] |access-date= }}</ref>
!% 1980
!% 1990
!% 2000
!% 2010
!style="background-color: #ffffb3;" |% 2020
|-
|[[Non-Hispanic or Latino whites|White]] alone (NH)
|415,984
|392,131
|352,355
|303,609
|style='background: #ffffe6; |275,902
|70.83%
|60.36%
|49.83%
|42.26%
|style='background: #ffffe6; |36.09%
|-
|[[Non-Hispanic or Latino African Americans|Black or African American]] alone (NH)
|34,730
|34,000
|23,778
|18,763
|style='background: #ffffe6; |14,701
|5.91%
|5.23%
|3.36%
|2.61%
|style='background: #ffffe6; |1.92%
|-
|[[Native Americans in the United States|Native American]] or [[Alaska Native]] alone (NH)
|2,481
|2,349
|1,546
|1,125
|style='background: #ffffe6; |1,021
|0.42%
|0.36%
|0.22%
|0.16%
|style='background: #ffffe6; |0.13%
|-
|[[Asian Americans|Asian]] alone (NH)
|56,305
|105,559
|140,313
|175,934
|style='background: #ffffe6; |227,783
|9.59%
|16.25%
|19.84%
|24.49%
|style='background: #ffffe6; |29.80%
|-
|[[Native Hawaiian]] or [[Pacific Islander Americans|Pacific Islander]] alone (NH)
|x <ref>included in the Asian category in the 1980 Census</ref>
|x <ref>included in the Asian category in the 1990 Census</ref>
|9,112
|9,884
|style='background: #ffffe6; |8,840
|x
|x
|1.29%
|1.38%
|style='background: #ffffe6; |1.16%
|-
|[[Race and ethnicity in the United States census|Other race]] alone (NH)
|4,490
|957
|2,217
|2,709
|style='background: #ffffe6; |5,840
|0.76%
|0.15%
|0.31%
|0.38%
|style='background: #ffffe6; |0.76%
|-
|[[Multiracial Americans|Mixed race or Multiracial]] (NH)
|x <ref>not an option in the 1980 Census</ref>
|x <ref>not an option in the 1990 Census</ref>
|23,132
|23,925
|style='background: #ffffe6; |38,969
|x
|x
|3.27%
|3.33%
|style='background: #ffffe6; |5.10%
|-
|[[Hispanic and Latino Americans|Hispanic or Latino]] (any race)
|73,339
|114,627
|154,708
|182,502
|style='background: #ffffe6; |191,386
|12.49%
|17.65%
|21.88%
|25.40%
|style='background: #ffffe6; |25.04%
|-
|'''Total'''
|'''587,329'''
|'''649,623'''
|'''707,161'''
|'''718,451'''
|style='background: #ffffe6; |'''764,442 '''
|'''100.00%'''
|'''100.00%'''
|'''100.00%'''
|'''100.00%'''
|style='background: #ffffe6; |'''100.00%'''
|}

As of the [[2020 United States census|2020 census]], the county had a population of 764,442 and a median age of 39.9 years. 20.2% of residents were under the age of 18 and 16.5% were 65 years of age or older; for every 100 females there were 97.6 males, and for every 100 females age 18 and over there were 95.6 males age 18 and over.<ref name="Census2020DP">{{cite web|title=2020 Decennial Census Demographic Profile (DP1)|url=https://api.census.gov/data/2020/dec/dp?get=NAME,DP1_0021P,DP1_0024P,DP1_0025C,DP1_0049C,DP1_0045C,DP1_0069C,DP1_0073C,DP1_0125P,DP1_0126P,DP1_0129P,DP1_0138P,DP1_0139P,DP1_0141P,DP1_0142P,DP1_0143P,DP1_0145P,DP1_0146P,DP1_0147C,DP1_0148C,DP1_0149C,DP1_0156C,DP1_0157C,DP1_0158C,DP1_0159P,DP1_0160P&for=county%3A081&in=state%3A06|website=United States Census Bureau|year=2021|access-date=December 21, 2025|df=mdy}}</ref>

The racial makeup of the county was 39.3% White, 2.1% Black or African American, 0.9% American Indian and Alaska Native, 30.1% Asian, 1.2% Native Hawaiian and Pacific Islander, 14.1% from some other race, and 12.3% from two or more races. Hispanic or Latino residents of any race comprised 25.0% of the population.<ref name="Census2020PL">{{cite web|title=2020 Decennial Census Redistricting Data (Public Law 94-171)|url=https://api.census.gov/data/2020/dec/pl?get=NAME,P1_001N,P1_003N,P1_004N,P1_005N,P1_006N,P1_007N,P1_008N,P1_009N,P2_001N,P2_002N,H1_001N,H1_002N&for=county%3A081&in=state%3A06|website=United States Census Bureau|year=2021|access-date=December 21, 2025|df=mdy}}</ref>

98.3% of residents lived in urban areas, while 1.7% lived in rural areas.<ref name="Census2020DHC">{{cite web|title=2020 Decennial Census Demographic and Housing Characteristics (DHC)|url=https://api.census.gov/data/2020/dec/dhc?get=NAME,P2_002N,P2_003N&for=county%3A081&in=state%3A06|website=United States Census Bureau|year=2023|access-date=December 21, 2025|df=mdy}}</ref>

There were 269,417 households in the county, of which 32.9% had children under the age of 18 living with them and 24.1% had a female householder with no spouse or partner present. About 22.1% of all households were made up of individuals and 9.5% had someone living alone who was 65 years of age or older.<ref name="Census2020DP"/>

There were 283,693 housing units, of which 5.0% were vacant. Among occupied housing units, 56.5% were owner-occupied and 43.5% were renter-occupied. The homeowner vacancy rate was 0.6% and the rental vacancy rate was 4.9%.<ref name="Census2020DP"/>

===2012===
As of 2012, San Mateo County had one of the largest [[Tongan people|Tongan]] communities outside of [[Tonga]], with an estimated 13,000 [[Tongan American]]s.<ref name="smdj">{{cite news|url=http://www.smdailyjournal.com/article_preview.php?id=230806&title=Tongans%20mourn%20passing%20of%20king|title=Tongans mourn passing of king|date=March 20, 2012|work=[[San Mateo Daily Journal]]|access-date=January 31, 2020|url-status=dead|archive-url=https://web.archive.org/web/20130602110256/http://archives.smdailyjournal.com/article_preview.php?id=230806|archive-date=June 2, 2013}}</ref>
[[File:Ethnic Origins in San Mateo County, CA.png|thumb|342x342px|Ethnic origins in San Mateo County]]

===2010===
The [[2010 United States census]] reported that San Mateo County had a population of 718,451. The racial makeup of San Mateo County was 383,535 (53.4%) [[White (U.S. Census)|White]], 20,436 (2.8%) [[African American (U.S. census)|African American]], 3,306 (0.5%) [[Native American (U.S. Census)|Native American]], 178,118 (24.8%) [[Asian (U.S. Census)|Asian]] (9.8% Filipino, 9.0% Chinese, 1.9% Indian, 1.2% Japanese, 0.8% Korean, 0.5% Vietnamese, 0.3% Burmese, 0.1% Pakistani), 10,317 (1.4%) [[Pacific Islander (U.S. Census)|Pacific Islander]] (0.6% Tongan, 0.3% Samoan, 0.2% Fijian, 0.1% Native Hawaiian), 84,529 (11.8%) from [[Race (United States census)|other races]], and 38,210 (5.3%) from two or more races. [[Hispanic (U.S. Census)|Hispanic]] or [[Latino (U.S. Census)|Latino]] of any race were 182,502 persons (25.4%); 15.7% of San Mateo County is Mexican, 2.7% Salvadoran, 1.2% Guatemalan, 1.2% Nicaraguan, 0.7% Peruvian, 0.6% Puerto Rican, 0.2% Colombian, and 0.2% Cuban.<ref>{{USCensus2010CA}}</ref>

{| class="wikitable sortable collapsible collapsed" style="text-align: right"
! Demographic profile<ref>{{cite web |title=San Mateo County |website=Bay Area Census |url=http://www.bayareacensus.ca.gov/counties/SanMateoCounty.htm}}</ref>
! 2010
|-
| style="text-align:left" | Total Population || 718,451 - 100.0%
|-
| style="text-align:left" | One Race || 680,241 - 94.7%
|-
| style="text-align:left" | Not Hispanic or Latino || 535,949 - 74.6%
|-
| style="text-align:left" | White alone || 303,609 - 42.3%
|-
| style="text-align:left" | Black or African American alone || 18,763 - 2.6%
|-
| style="text-align:left" | American Indian and Alaska Native alone || 1,125 - 0.2%
|-
| style="text-align:left" | Asian alone || 175,934 - 24.5%
|-
| style="text-align:left" | Native Hawaiian and Other Pacific Islander alone || 9,884 - 1.4%
|-
| style="text-align:left" | Some other race alone || 2,709 - 0.4%
|-
| style="text-align:left" | Two or more races alone || 23,925 - 3.3%
|-
| style="text-align:left" | Hispanic or Latino (of any race) || 182,502 - 25.4%
|}

{| class="wikitable collapsible collapsed"
!colspan=10|Population reported at [[2010 United States census]]
|-
|style="text-align:center"|'''The County''' ||style="text-align:center"|'''Total<br />Population'''||style="text-align:center"|'''[[White (U.S. Census)|White]]''' ||style="text-align:center"|'''[[African American (U.S. census)|African<br />American]]''' || style="text-align:center" | '''[[Native American (U.S. Census)|Native<br />American]]''' || style="text-align:center" | '''[[Asian (U.S. Census)|Asian]]''' || style="text-align:center" | '''[[Pacific Islander (U.S. Census)|Pacific<br />Islander]]''' || style="text-align:center" | '''[[Race (United States census)|other<br />races]]''' || style="text-align:center" | '''two or<br />more races''' ||style="text-align:center"|'''[[Hispanic (U.S. Census)|Hispanic]]<br />or [[Latino (U.S. Census)|Latino]]<br />(of any race)'''
|-
|''' San Mateo County'''
| style="text-align:right"|718,451|| style="text-align:right"|383,535|| style="text-align:right"|20,436|| style="text-align:right"|3,306|| style="text-align:right"|178,118|| style="text-align:right"|10,317|| style="text-align:right"|84,529|| style="text-align:right"|38,210|| style="text-align:right"|182,502
|-
|style="text-align:center"|'''[[Incorporated city|Incorporated<br />cities and towns]]''' ||style="text-align:center"|'''Total<br />Population'''||style="text-align:center"|'''[[White (U.S. Census)|White]]''' ||style="text-align:center"|'''[[African American (U.S. census)|African<br />American]]''' || style="text-align:center" | '''[[Native American (U.S. Census)|Native<br />American]]''' || style="text-align:center" | '''[[Asian (U.S. Census)|Asian]]''' || style="text-align:center" | '''[[Pacific Islander (U.S. Census)|Pacific<br />Islander]]''' || style="text-align:center" | '''[[Race (United States census)|other<br />races]]''' || style="text-align:center" | '''two or<br />more races''' ||style="text-align:center"|'''[[Hispanic (U.S. Census)|Hispanic]]<br />or [[Latino (U.S. Census)|Latino]]<br />(of any race)'''
|-
|'''[[Atherton, California|Atherton]]'''
| style="text-align:right"|6,914|| style="text-align:right"|5,565|| style="text-align:right"|75|| style="text-align:right"|7|| style="text-align:right"|911|| style="text-align:right"|45|| style="text-align:right"|95|| style="text-align:right"|216|| style="text-align:right"|268
|-
|'''[[Belmont, California|Belmont]]'''
| style="text-align:right"|25,835|| style="text-align:right"|17,455|| style="text-align:right"|423|| style="text-align:right"|72|| style="text-align:right"|5,151|| style="text-align:right"|198|| style="text-align:right"|964|| style="text-align:right"|1,572|| style="text-align:right"|2,977
|-
|'''[[Brisbane, California|Brisbane]]'''
| style="text-align:right"|4,282|| style="text-align:right"|2,578|| style="text-align:right"|80|| style="text-align:right"|21|| style="text-align:right"|1,084|| style="text-align:right"|41|| style="text-align:right"|182|| style="text-align:right"|296|| style="text-align:right"|712
|-
|'''[[Burlingame, California|Burlingame]]'''
| style="text-align:right"|28,806|| style="text-align:right"|19,510|| style="text-align:right"|360|| style="text-align:right"|74|| style="text-align:right"|5,841|| style="text-align:right"|139|| style="text-align:right"|1,451|| style="text-align:right"|1,431|| style="text-align:right"|3,966
|-
|'''[[Colma, California|Colma]]'''
| style="text-align:right"|1,792|| style="text-align:right"|620|| style="text-align:right"|59|| style="text-align:right"|7|| style="text-align:right"|619|| style="text-align:right"|9|| style="text-align:right"|366|| style="text-align:right"|112|| style="text-align:right"|708
|-
|'''[[Daly City, California|Daly City]]'''
| style="text-align:right"|101,123|| style="text-align:right"|23,842|| style="text-align:right"|3,600|| style="text-align:right"|404|| style="text-align:right"|56,267|| style="text-align:right"|805|| style="text-align:right"|11,236|| style="text-align:right"|4,969|| style="text-align:right"|23,929
|-
|'''[[East Palo Alto, California|East Palo Alto]]'''
| style="text-align:right"|28,155|| style="text-align:right"|8,104|| style="text-align:right"|4,704|| style="text-align:right"|120|| style="text-align:right"|1,057|| style="text-align:right"|2,118|| style="text-align:right"|10,694|| style="text-align:right"|1,358|| style="text-align:right"|18,147
|-
|'''[[Foster City, California|Foster City]]'''
| style="text-align:right"|30,567|| style="text-align:right"|13,912|| style="text-align:right"|576|| style="text-align:right"|29|| style="text-align:right"|13,746|| style="text-align:right"|189|| style="text-align:right"|575|| style="text-align:right"|1,540|| style="text-align:right"|1,995
|-
|'''[[Half Moon Bay, California|Half Moon Bay]]'''
| style="text-align:right"|11,324|| style="text-align:right"|8,580|| style="text-align:right"|82|| style="text-align:right"|71|| style="text-align:right"|490|| style="text-align:right"|9|| style="text-align:right"|1,710|| style="text-align:right"|382|| style="text-align:right"|3,563
|-
|'''[[Hillsborough, California|Hillsborough]]'''
| style="text-align:right"|10,825|| style="text-align:right"|7,178|| style="text-align:right"|42|| style="text-align:right"|7|| style="text-align:right"|3,044|| style="text-align:right"|23|| style="text-align:right"|109|| style="text-align:right"|422|| style="text-align:right"|373
|-
|'''[[Menlo Park, California|Menlo Park]]'''
| style="text-align:right"|32,026|| style="text-align:right"|22,494|| style="text-align:right"|1,551|| style="text-align:right"|156|| style="text-align:right"|3,157|| style="text-align:right"|454|| style="text-align:right"|2,776|| style="text-align:right"|1,438|| style="text-align:right"|5,902
|-
|'''[[Millbrae, California|Millbrae]]'''
| style="text-align:right"|21,532|| style="text-align:right"|10,177|| style="text-align:right"|179|| style="text-align:right"|33|| style="text-align:right"|9,205|| style="text-align:right"|214|| style="text-align:right"|776|| style="text-align:right"|948|| style="text-align:right"|2,555
|-
|'''[[Pacifica, California|Pacifica]]'''
| style="text-align:right"|37,234|| style="text-align:right"|24,166|| style="text-align:right"|976|| style="text-align:right"|206|| style="text-align:right"|7,230|| style="text-align:right"|315|| style="text-align:right"|1,703|| style="text-align:right"|2,638|| style="text-align:right"|6,243
|-
|'''[[Portola Valley, California|Portola Valley]]'''
| style="text-align:right"|4,353|| style="text-align:right"|3,960|| style="text-align:right"|12|| style="text-align:right"|5|| style="text-align:right"|242|| style="text-align:right"|1|| style="text-align:right"|29|| style="text-align:right"|104|| style="text-align:right"|175
|-
|'''[[Redwood City, California|Redwood City]]'''
| style="text-align:right"|76,815|| style="text-align:right"|46,255|| style="text-align:right"|1,881|| style="text-align:right"|511|| style="text-align:right"|8,216|| style="text-align:right"|795|| style="text-align:right"|14,967|| style="text-align:right"|4,190|| style="text-align:right"|29,810
|-
|'''[[San Bruno, California|San Bruno]]'''
| style="text-align:right"|41,114|| style="text-align:right"|20,350|| style="text-align:right"|942|| style="text-align:right"|246|| style="text-align:right"|10,423|| style="text-align:right"|1,377|| style="text-align:right"|5,075|| style="text-align:right"|2,701|| style="text-align:right"|12,016
|-
|'''[[San Carlos, California|San Carlos]]'''
| style="text-align:right"|28,406|| style="text-align:right"|22,497|| style="text-align:right"|233|| style="text-align:right"|65|| style="text-align:right"|3,267|| style="text-align:right"|70|| style="text-align:right"|827|| style="text-align:right"|1,447|| style="text-align:right"|2,855
|-
|'''[[San Mateo, California|San Mateo]]'''
| style="text-align:right"|97,207|| style="text-align:right"|56,214|| style="text-align:right"|2,296|| style="text-align:right"|505|| style="text-align:right"|18,384|| style="text-align:right"|1,998|| style="text-align:right"|12,264|| style="text-align:right"|5,546|| style="text-align:right"|25,815
|-
|'''[[South San Francisco, California|South San Francisco]]'''
| style="text-align:right"|63,632|| style="text-align:right"|23,760|| style="text-align:right"|1,625|| style="text-align:right"|395|| style="text-align:right"|23,293|| style="text-align:right"|1,111|| style="text-align:right"|9,598|| style="text-align:right"|3,850|| style="text-align:right"|21,645
|-
|'''[[Woodside, California|Woodside]]'''
| style="text-align:right"|5,287|| style="text-align:right"|4,717|| style="text-align:right"|23|| style="text-align:right"|4|| style="text-align:right"|332|| style="text-align:right"|4|| style="text-align:right"|63|| style="text-align:right"|144|| style="text-align:right"|243
|-
|style="text-align:center"|'''[[Census-designated place|Census-designated<br />places]]''' ||style="text-align:center"|'''Total<br />Population'''||style="text-align:center"|'''[[White (U.S. Census)|White]]''' ||style="text-align:center"|'''[[African American (U.S. census)|African<br />American]]''' || style="text-align:center" | '''[[Native American (U.S. Census)|Native<br />American]]''' || style="text-align:center" | '''[[Asian (U.S. Census)|Asian]]''' || style="text-align:center" | '''[[Pacific Islander (U.S. Census)|Pacific<br />Islander]]''' || style="text-align:center" | '''[[Race (United States census)|other<br />races]]''' || style="text-align:center" | '''two or<br />more races''' ||style="text-align:center"|'''[[Hispanic (U.S. Census)|Hispanic]]<br />or [[Latino (U.S. Census)|Latino]]<br />(of any race)'''
|-
|'''[[Broadmoor, California|Broadmoor]]'''
| style="text-align:right"|4,176|| style="text-align:right"|1,705|| style="text-align:right"|100|| style="text-align:right"|30|| style="text-align:right"|1,676|| style="text-align:right"|44|| style="text-align:right"|359|| style="text-align:right"|262|| style="text-align:right"|981
|-
|'''[[El Granada, California|El Granada]]'''
| style="text-align:right"|5,467|| style="text-align:right"|4,608|| style="text-align:right"|45|| style="text-align:right"|38|| style="text-align:right"|190|| style="text-align:right"|5|| style="text-align:right"|336|| style="text-align:right"|245|| style="text-align:right"|813
|-
|'''[[Emerald Lake Hills, California|Emerald Lake Hills]]'''
| style="text-align:right"|4,278|| style="text-align:right"|3,655|| style="text-align:right"|39|| style="text-align:right"|5|| style="text-align:right"|322|| style="text-align:right"|15|| style="text-align:right"|56|| style="text-align:right"|186|| style="text-align:right"|288
|-
|'''[[Highlands-Baywood Park, California|Highlands-Baywood Park]]'''
| style="text-align:right"|4,027|| style="text-align:right"|2,657|| style="text-align:right"|53|| style="text-align:right"|9|| style="text-align:right"|1,017|| style="text-align:right"|17|| style="text-align:right"|47|| style="text-align:right"|227|| style="text-align:right"|306
|-
|'''[[Ladera, California|Ladera]]'''
| style="text-align:right"|928|| style="text-align:right"|811|| style="text-align:right"|13|| style="text-align:right"|0|| style="text-align:right"|16|| style="text-align:right"|2|| style="text-align:right"|18|| style="text-align:right"|68|| style="text-align:right"|69
|-
|'''[[La Honda, California|La Honda]]'''
| style="text-align:right"|1,426|| style="text-align:right"|1,269|| style="text-align:right"|3|| style="text-align:right"|1|| style="text-align:right"|98|| style="text-align:right"|0|| style="text-align:right"|5|| style="text-align:right"|50|| style="text-align:right"|33
|-
|'''[[Loma Mar, California|Loma Mar]]'''
| style="text-align:right"|113|| style="text-align:right"|101|| style="text-align:right"|2|| style="text-align:right"|0|| style="text-align:right"|3|| style="text-align:right"|0|| style="text-align:right"|0|| style="text-align:right"|7|| style="text-align:right"|12
|-
|'''[[Montara, California|Montara]]'''
| style="text-align:right"|2,909|| style="text-align:right"|2,491|| style="text-align:right"|16|| style="text-align:right"|21|| style="text-align:right"|142|| style="text-align:right"|1|| style="text-align:right"|97|| style="text-align:right"|141|| style="text-align:right"|324
|-
|'''[[Moss Beach, California|Moss Beach]]'''
| style="text-align:right"|3,103|| style="text-align:right"|2,280|| style="text-align:right"|25|| style="text-align:right"|43|| style="text-align:right"|118|| style="text-align:right"|9|| style="text-align:right"|494|| style="text-align:right"|134|| style="text-align:right"|903
|-
|'''[[North Fair Oaks, California|North Fair Oaks]]'''
| style="text-align:right"|14,687|| style="text-align:right"|7,060|| style="text-align:right"|235|| style="text-align:right"|143|| style="text-align:right"|548|| style="text-align:right"|219|| style="text-align:right"|5,728|| style="text-align:right"|754|| style="text-align:right"|10,731
|-
|'''[[Pescadero, California|Pescadero]]'''
| style="text-align:right"|643|| style="text-align:right"|314|| style="text-align:right"|2|| style="text-align:right"|2|| style="text-align:right"|5|| style="text-align:right"|1|| style="text-align:right"|294|| style="text-align:right"|25|| style="text-align:right"|402
|-
|'''[[West Menlo Park, California|West Menlo Park]]'''
| style="text-align:right"|3,659|| style="text-align:right"|2,983|| style="text-align:right"|28|| style="text-align:right"|2|| style="text-align:right"|416|| style="text-align:right"|4|| style="text-align:right"|52|| style="text-align:right"|174|| style="text-align:right"|201
|-
|style="text-align:center"|'''Other<br />[[unincorporated area]]s''' ||style="text-align:center"|'''Total<br />Population'''||style="text-align:center"|'''[[White (U.S. Census)|White]]''' ||style="text-align:center"|'''[[African American (U.S. census)|African<br />American]]''' || style="text-align:center" | '''[[Native American (U.S. Census)|Native<br />American]]''' || style="text-align:center" | '''[[Asian (U.S. Census)|Asian]]''' || style="text-align:center" | '''[[Pacific Islander (U.S. Census)|Pacific<br />Islander]]''' || style="text-align:center" | '''[[Race (United States census)|other<br />races]]''' || style="text-align:center" | '''two or<br />more races''' ||style="text-align:center"|'''[[Hispanic (U.S. Census)|Hispanic]]<br />or [[Latino (U.S. Census)|Latino]]<br />(of any race)'''
|-
|All others not CDPs (combined)
| style="text-align:right"|15,806|| style="text-align:right"|11,667|| style="text-align:right"|156|| style="text-align:right"|74|| style="text-align:right"|1,608|| style="text-align:right"|85|| style="text-align:right"|1,583|| style="text-align:right"|633|| style="text-align:right"|3,542
|}

===2000===
[[File:USA San Mateo County, California age pyramid.svg|thumb|left|200px|Age distribution (2000 census)]]

As of the [[census]] of 2009,<ref name="GR8">{{cite web|url=https://www.census.gov|publisher=[[United States Census Bureau]]|access-date=May 14, 2011|title=U.S. Census website}}</ref> there were 714,936 people, 258,648 households, and 174,582 families residing in the county. The [[population density]] was {{convert|2,753|/mi2|/km2|disp=preunit|people&nbsp;|people|}}. There were 284,471 housing units at an average density of {{convert|789|/mi2|/km2|disp=preunit|units&nbsp;|units|}}. 7.4% were of [[Italian people|Italian]], 7.1% [[Irish people|Irish]], 7.0% [[german people|German]] and 5.3% [[English people|English]] ancestry according to [[Census 2000]]. 46.9% spoke [[English language|English]], 28.4% [[Spanish language|Spanish]], 6.2% [[Tagalog language|Tagalog]], 4.0% [[Chinese language|Chinese]] or [[Standard Mandarin|Mandarin]] and 1.1% [[Standard Cantonese|Cantonese]], and other language 4.2%, as their first language from estimate census 2009.

There were 258,648 households, out of which 30% had children under the age of 18, 48.6% were [[Marriage|married couples]] living together, 14.7% had a female householder with no husband present, and 41.7% were non-families. 31.5% of all households were made up of individuals, and 6.2% had someone living alone who was 65 years of age or older. The average household size was 3.79 and the average family size was 4.44.

In the county, the population was spread out, with 28.6% under the age of 18, 15.9% from 18 to 24, 25.8% from 25 to 44, 21% from 45 to 64, and 9.7% who were 65 years of age or older. The median age was 31 years. For every 100 females there were 97.8 males. For every 100 females age 18 and over, there were 95.1 males.

The median income for a household in the county was $69,306, and the median income for a family was $77,737. Males had a median income of $48,342 versus $45,383 for females. The [[per capita income]] for the county was $36,045. About 6.42% of families and 9.51% of the population were below the [[poverty line]], including 10.01% of those under age 18 and 8.52% of those age 65 or over.

{{clear}}
==Government==
San Mateo County has a five-member [[San Mateo County Board of Supervisors|Board of Supervisors]], representing five geographic districts. The Board of Supervisors were formerly elected [[at-large]] (by voters across the entire county) until November 2012. On November 6, 2012, Measure B passed<ref>{{cite web|title=Election Results November 6, 2012 Presidential General Election|url=https://www.shapethefuture.org/elections/results/2012/nov/results.asp#c-1203|work=Shape the Future. Vote!|publisher=Registration & Elections Division|access-date=July 4, 2013|date=November 6, 2012|archive-url=https://web.archive.org/web/20130520215319/https://www.shapethefuture.org/elections/results/2012/nov/results.asp#c-1203|archive-date=May 20, 2013|url-status=dead}}</ref> to amend the San Mateo County Charter so that each member of the Board of Supervisors would be elected by voters in his or her district.<ref>{{cite web|title=Measure B|url=https://www.shapethefuture.org/elections/2012/nov/documents/14_ENG_M_B.pdf|work=San Mateo County|publisher=Registration & Elections Division|access-date=July 4, 2013|date=August 2012}}</ref>
* District 1 is represented by [[Jackie Speier]].
* District 2 is represented by Noelia Corzo.
* District 3 is represented by Ray Mueller.
* District 4 is represented by Warren Slocum.
* District 5 is represented by David Canepa.
The other county elected officials are:
{| class="wikitable"
|+
!Elected Office
!Name
|-
|Assessor–County Clerk–Recorder
|Mark Church
|-
|Controller
|Juan Raizoga
|-
|Coroner
|Robert Foucrault
|-
|District Attorney
|Stephen M. Wagstaffe
|-
|Sheriff
|''Vacant''
|-
|Treasurer–Tax Collector
|Sandie Arnott
|}
San Mateo County is split between California's [[California's 15th congressional district|15th]] and [[California's 16th congressional district|16th]] congressional districts, represented by {{Representative|cacd|15}} and {{Representative|cacd|16}}, respectively.<ref>{{Cite GovTrack|CA|15|access-date=January 11, 2023}}</ref>

In the [[California State Assembly]], San Mateo County is split between three legislative districts:<ref>{{Cite web
 |url          = http://wedrawthelines.ca.gov/downloads/meeting_handouts_072011/handouts_20110729_q2_ad_finaldraft_splits.zip
 |title        = Communities of Interest&nbsp;— County
 |publisher    = California Citizens Redistricting Commission
 |access-date   = September 28, 2014
|archive-url  = https://web.archive.org/web/20151023054757/http://wedrawthelines.ca.gov/downloads/meeting_handouts_072011/handouts_20110729_q2_ad_finaldraft_splits.zip
 |archive-date = October 23, 2015
|url-status     = dead
 |df           = dmy-all
}}</ref>
* {{Representative|caad|19|fmt=adistrict}},
* {{Representative|caad|21|fmt=adistrict}}, and
* {{Representative|caad|23|fmt=adistrict}}.

In the [[California State Senate]], San Mateo is split between the [[California's 11th State Senate district|11th]] and [[California's 13th State Senate district|13th]] districts, represented by {{Representative|casd|11}} and {{Representative|casd|13}}, respectively.<ref>{{Cite web
 |url          = http://wedrawthelines.ca.gov/downloads/meeting_handouts_072011/handouts_20110729_q2_sd_finaldraft_splits.zip
 |title        = Communities of Interest&nbsp;— County
 |publisher    = California Citizens Redistricting Commission
 |access-date   = September 28, 2014
|archive-url  = https://web.archive.org/web/20151023054153/http://wedrawthelines.ca.gov/downloads/meeting_handouts_072011/handouts_20110729_q2_sd_finaldraft_splits.zip
 |archive-date = October 23, 2015
|url-status     = dead
 |df           = dmy-all
}}</ref>

==Politics==

===Presidential election results and voter registration===
{{PresHead|place=San Mateo County, California|source=<ref>{{Cite web|url=http://uselectionatlas.org/RESULTS/|title = Dave Leip's Atlas of U.S. Presidential Elections}}</ref>|source2=<ref group=note>This total comprised 2,825 votes for [[Progressive Party (United States, 1912)|Progressive]] [[Theodore Roosevelt]] (who was official Republican nominee in California), 827 votes for [[Socialist Party of America|Socialist]] [[Eugene V. Debs]] and 80 votes for [[Prohibition Party]] nominee [[Eugene W. Chafin]].</ref>}}
<!-- PresRow should be {{PresRow|Year|Winning party|GOP vote #|Dem vote #|3rd party vote #|State}} -->
{{PresRow|1880|Republican|760|720|10|California}}
{{PresRow|1884|Republican|950|750|17|California}}
{{PresRow|1888|Republican|1,121|980|16|California}}
{{PresRow|1892|Republican|1,088|1,020|44|California}}
{{PresRow|1896|Republican|1,607|987|36|California}}
{{PresRow|1900|Republican|1,645|914|52|California}}
{{PresRow|1904|Republican|2,146|851|138|California}}
{{PresRow|1908|Republican|2,865|1,314|375|California}}
{{PresRow|1912|Democratic|7|3,246|3,732|California}}
{{PresRow|1916|Republican|5,207|4,485|719|California}}
{{PresRow|1920|Republican|7,205|1,958|1,054|California}}
{{PresRow|1924|Republican|8,126|771|5,805|California}}
{{PresRow|1928|Republican|14,360|9,755|277|California}}
{{PresRow|1932|Democratic|13,442|19,094|1,343|California}}
{{PresRow|1936|Democratic|13,650|27,087|511|California}}
{{PresRow|1940|Democratic|26,539|29,831|581|California}}
{{PresRow|1944|Democratic|33,590|34,594|158|California}}
{{PresRow|1948|Republican|48,909|34,215|3,148|California}}
{{PresRow|1952|Republican|92,279|52,149|651|California}}
{{PresRow|1956|Republican|100,049|63,637|217|California}}
{{PresRow|1960|Republican|104,570|97,154|528|California}}
{{PresRow|1964|Democratic|77,916|140,978|297|California}}
{{PresRow|1968|Democratic|98,654|106,519|20,495|California}}
{{PresRow|1972|Republican|135,377|109,745|11,175|California}}
{{PresRow|1976|Republican|117,338|102,896|11,507|California}}
{{PresRow|1980|Republican|116,491|87,335|34,811|California}}
{{PresRow|1984|Republican|135,185|122,268|3,178|California}}
{{PresRow|1988|Democratic|109,261|141,859|3,360|California}}
{{PresRow|1992|Democratic|75,080|149,232|52,196|California}}
{{PresRow|1996|Democratic|73,508|152,304|25,720|California}}
{{PresRow|2000|Democratic|80,296|166,757|12,346|California}}
{{PresRow|2004|Democratic|83,315|197,922|3,620|California}}
{{PresRow|2008|Democratic|75,057|222,826|5,409|California}}
{{PresRow|2012|Democratic|72,756|206,085|6,879|California}}
{{PresRow|2016|Democratic|57,929|237,882|18,573|California}}
{{PresRow|2020|Democratic|75,584|291,496|7,171|California}}
{{PresRow|2024|Democratic|76,616|242,957|10,992|California}}
{{PresFoot}}

{| class="wikitable collapsible collapsed"
|-
! colspan="3" | Population and registered voters
|-
! scope="row" style="text-align: left;" | Total population<ref name="US-CB-B02001">U.S. Census Bureau. American Community Survey, 2011 American Community Survey 5-Year Estimates, Table B02001. [https://www.census.gov U.S. Census website]. Retrieved October 26, 2013.</ref>
| colspan="2" | 711,622
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Registered voters<ref name="CA-SS">California Secretary of State. [http://www.sos.ca.gov/elections/ror/ror-pages/ror-odd-year-2013/political-sub.pdf February 10, 2013 - Report of Registration] {{webarchive|url=https://web.archive.org/web/20130727173649/http://www.sos.ca.gov/elections/ror/ror-pages/ror-odd-year-2013/political-sub.pdf |date=July 27, 2013 }}. Retrieved October 31, 2013.</ref><ref name="PCT-RV" group=note>Percentage of registered voters with respect to total population. Percentages of party members with respect to registered voters follow.</ref>
| 360,786
| 50.7%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Democratic<ref name="CA-SS"/>
| 185,134
| 51.3%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Republican<ref name="CA-SS"/>
| 69,925
| 19.4%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Democratic&ndash;Republican spread<ref name="CA-SS"/>
| <span style="color: #0000ff;">'''+115,209'''</span>
| <span style="color: #0000ff;">'''+31.9%'''</span>
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;American Independent<ref name="CA-SS"/>
| 7,693
| 2.1%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Green<ref name="CA-SS"/>
| 2,521
| 0.7%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Libertarian<ref name="CA-SS"/>
| 1,852
| 0.5%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Peace and Freedom<ref name="CA-SS"/>
| 735
| 0.2%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Americans Elect<ref name="CA-SS"/>
| 14
| 0.0%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;Other<ref name="CA-SS"/>
| 754
| 0.2%
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;&nbsp;&nbsp;No party preference<ref name="CA-SS"/>
| 92,158
| 25.5%
|}

====Cities by population and voter registration====

{| class="wikitable collapsible collapsed sortable" style="width: 100%;"
|+ Cities by population and voter registration
! City
! data-sort-type="number" | Population<ref name="US-CB-B02001"/>
! data-sort-type="number" | Registered voters<ref name="CA-SS"/><br /><ref name="PCT-RV" group=note/>
! data-sort-type="number" | Democratic<ref name="CA-SS"/>
! data-sort-type="number" | Republican<ref name="CA-SS"/>
! data-sort-type="number" | D&ndash;R spread<ref name="CA-SS"/>
! data-sort-type="number" | Other<ref name="CA-SS"/>
! data-sort-type="number" | No party preference<ref name="CA-SS"/>
|-
| [[Atherton, California|Atherton]] || 7,137 || 69.4% || 34.7% || 31.1% || <span style="color: #800080;">'''+3.6%'''</span> || 3.9% || 30.3%
|-
| [[Belmont, California|Belmont]] || 26,941 || 58.7% || 48.5% || 16.0% || <span style="color: #0000ff;">'''+32.5%'''</span> || 3.9% || 31.6%
|-
| [[Brisbane, California|Brisbane]] || 4,671 || 59.8% || 52.1% || 10.4% || <span style="color: #0000ff;">'''+41.7%'''</span> || 5.1% || 32.4%
|-
| [[Burlingame, California|Burlingame]] || 30,889 || 57.5% || 47.5% || 17.2% || <span style="color: #0000ff;">'''+30.3%'''</span> || 4.0% || 31.3%
|-
| [[Colma, California|Colma]] || 1,489 || 47.1% || 55.5% || 11.0% || <span style="color: #0000ff;">'''+44.5%'''</span> || 3.7% || 29.8%
|-
| [[Daly City, California|Daly City]] || 106,280 || 43.9% || 51.8% || 9.6% || <span style="color: #0000ff;">'''+42.2%'''</span> || 3.3% || 35.3%
|-
| [[East Palo Alto, California|East Palo Alto]] || 29,314 || 35.9% || 57.4% || 6.1% || <span style="color: #0000ff;">'''+51.3%'''</span> || 4.4% || 32.1%
|-
| [[Foster City, California|Foster City]] || 33,901 || 48.9% || 44.3% || 16.6% || <span style="color: #2b00d6;">'''+27.7%'''</span> || 2.9% || 36.2%
|-
| [[Half Moon Bay, California|Half Moon Bay]] || 12,932 || 58.4% || 47.7% || 18.3% || <span style="color: #2b00d6;">'''+29.4%'''</span> || 5.6% || 28.4%
|-
| [[Hillsborough, California|Hillsborough]] || 11,387 || 68.5% || 33.8% || 30.0% || <span style="color: #800080;">'''+3.8%'''</span> || 3.9% || 32.3%
|-
| [[Menlo Park, California|Menlo Park]] || 34,698 || 55.7% || 51.6% || 15.5% || <span style="color: #0000ff;">'''+36.1%'''</span> || 3.5% || 29.4%
|-
| [[Millbrae, California|Millbrae]] || 22,394 || 57.4% || 44.6% || 15.9% || <span style="color: #2b00d6;">'''+28.7%'''</span> || 3.8% || 35.7%
|-
| [[Pacifica, California|Pacifica]] || 38,546 || 64.9% || 53.6% || 13.1% || <span style="color: #0000ff;">'''+40.5%'''</span> || 4.7% || 28.6%
|-
| [[Portola Valley, California|Portola Valley]] || 4,568 || 74.7% || 46.3% || 22.4% || <span style="color: #2b00d6;">'''+23.9%'''</span> || 3.8% || 27.5%
|-
| [[Redwood City, California|Redwood City]] || 85,925 || 48.7% || 50.7% || 14.9% || <span style="color: #0000ff;">'''+35.8%'''</span> || 5.9% || 30.5%
|-
| [[San Bruno, California|San Bruno]] || 42,807 || 53.3% || 52.0% || 13.4% || <span style="color: #0000ff;">'''+38.6%'''</span> || 3.9% || 30.7%
|-
| [[San Carlos, California|San Carlos]] || 30,185 || 65.3% || 48.7% || 18.6% || <span style="color: #0000ff;">'''+30.1%'''</span> || 3.8% || 28.9%
|-
| [[San Mateo, California|San Mateo]] || 104,430 || 52.6% || 50.1% || 15.5% || <span style="color: #0000ff;">'''+34.6%'''</span> || 3.9% || 30.5%
|-
| [[South San Francisco, California|South San Francisco]] || 67,789 || 48.6% || 53.5% || 10.9% || <span style="color: #0000ff;">'''+42.6%'''</span> || 3.5% || 32.1%
|-
| [[Woodside, California|Woodside]] || 5,458 || 75.2% || 40.4% || 26.6% || <span style="color: #2b00d6;">'''+13.8%'''</span> || 4.5% || 28.5%
|}

===Overview===
The California Secretary of State, as of February 2019, reports that San Mateo County has 404,958 registered voters.<ref>{{Cite web |title=Report of Registration as of February 10, 2019 Registration by Political Subdivision by County |url=https://elections.cdn.sos.ca.gov/ror/ror-odd-year-2019/politicalsub.pdf |website=elections.cdn.sos.ca.gov}}</ref> Of those voters, 202,341 (50%) are registered Democratic, 60,045 (14.3%) are registered Republican, 15,834 (3.9%) are registered with other political parties, and 126,738 (31.3%) [[declined to state]] a political party preference. Every city, town, and unincorporated area of San Mateo County has more registered Democrats than Republicans.

On November 4, 2008, San Mateo County voted 61.8% against [[2008 California Proposition 8|Proposition 8]], which amended the California Constitution to ban same-sex marriages.<ref>{{cite web
 |url          = http://www.sos.ca.gov/elections/sov/2008_general/57_65_ballot_measures.pdf
 |author       = California Secretary of State
 |title        = State Ballot Measures (Proposition Numbers 1A-12) by County
 |access-date   = June 14, 2009
|archive-url  = https://web.archive.org/web/20090612235853/http://www.sos.ca.gov/elections/sov/2008_general/57_65_ballot_measures.pdf
 |archive-date = June 12, 2009
|url-status     = dead
 |df           = dmy-all
}}</ref>

==Crime==

The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense{{when|date=June 2021}}.

{| class="wikitable collapsible"
|-
! colspan="3" | Population and crime rates
|-
! scope="row" style="text-align: left;" | Population<ref name="US-CB-B02001"/>
| colspan="2" | 711,622
|-
! scope="row" style="text-align: left;" | Violent crime<ref name="CA-DOJ-T11">Office of the Attorney General, Department of Justice, State of California. [http://stats.doj.ca.gov/cjsc_stats/prof09/00/11.pdf Table 11: Crimes &ndash; 2009] {{webarchive|url=https://web.archive.org/web/20131202222315/http://stats.doj.ca.gov/cjsc_stats/prof09/00/11.pdf |date=December 2, 2013 }}. Retrieved November 14, 2013.</ref>
| 2,072 || 2.91
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Homicide<ref name="CA-DOJ-T11"/>
| 16 || 0.02
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Forcible rape<ref name="CA-DOJ-T11"/>
| 128 || 0.18
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Robbery<ref name="CA-DOJ-T11"/>
| 734 || 1.03
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Aggravated assault<ref name="CA-DOJ-T11"/>
| 1,194 || 1.68
|-
! scope="row" style="text-align: left;" | Property crime<ref name="CA-DOJ-T11"/>
| 8,677 || 12.19
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Burglary<ref name="CA-DOJ-T11"/>
| 3,072 || 4.32
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Larceny-theft<ref name="CA-DOJ-T11"/><ref name="LT-note group=note">Only larceny-theft cases involving property over $400 in value are reported as property crimes.</ref>
| 10,712 || 15.05
|-
! scope="row" style="text-align: left;" | &nbsp;&nbsp;Motor vehicle theft<ref name="CA-DOJ-T11"/>
| 1,988 || 2.79
|-
! scope="row" style="text-align: left;" | Arson<ref name="CA-DOJ-T11"/>
| 125 || 0.18
|}

===Cities by population and crime rates===

{| class="wikitable collapsible sortable" style="width: 100%;"
|-
! City
! data-sort-type="number" | Population<ref name="FBI-UCR-T8">United States Department of Justice, Federal Bureau of Investigation. [https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2012/crime-in-the-u.s.-2012/tables/8tabledatadecpdf/table-8-state-cuts/table_8_offenses_known_to_law_enforcement_by_california_by_city_2012.xls Crime in the United States, 2012, Table 8 (California)]. Retrieved November 14, 2013.</ref>
! data-sort-type="number" | Violent crimes<ref name="FBI-UCR-T8"/>
! data-sort-type="number" | Violent crime rate<br />per 1,000 persons
! data-sort-type="number" | Property crimes<ref name="FBI-UCR-T8"/>
! data-sort-type="number" | Property crime rate<br />per 1,000 persons
|-
| [[Atherton, California|Atherton]] || 7,060 || 6 || 0.85 || 124 || 17.56
|-
| [[Belmont, California|Belmont]] || 26,389 || 24 || 0.91 || 408 || 15.46
|-
| [[Brisbane, California|Brisbane]] || 4,374 || 6 || 1.37 || 142 || 32.46
|-
| [[Broadmoor, California|Broadmoor]] || 4,264 || 13 || 3.05 || 62 || 14.54
|-
| [[Burlingame, California|Burlingame]] || 29,427 || 61 || 2.07 || 707 || 24.03
|-
| [[Colma, California|Colma]] || 1,832 || 7 || 3.82 || 287 || 156.66
|-
| [[Daly City, California|Daly City]] || 103,311 || 216 || 2.09 || 1,803 || 17.45
|-
| [[East Palo Alto, California|East Palo Alto]] || 28,766 || 333 || 11.58 || 587 || 20.41
|-
| [[Foster City, California|Foster City]] || 31,230 || 18 || 0.58 || 345 || 11.05
|-
| [[Hillsborough, California|Hillsborough]] || 11,060 || 1 || 0.09 || 86 || 7.78
|-
| [[Menlo Park, California|Menlo Park]] || 32,713 || 53 || 1.62 || 625 || 19.11
|-
| [[Pacifica, California|Pacifica]] || 38,041 || 42 || 1.10 || 578 || 15.19
|-
| [[Redwood City, California|Redwood City]] || 78,466 || 208 || 2.65 || 1,800 || 22.94
|-
| [[San Bruno, California|San Bruno]] || 42,002 || 85 || 2.02 || 961 || 22.88
|-
| [[San Mateo, California|San Mateo]] || 99,303 || 261 || 2.63 || 1,876 || 18.89
|-
| [[South San Francisco, California|South San Francisco]] || 65,006 || 111 || 1.71 || 1,321 || 20.32
|-
! scope="row" style="text-align: left;" | Overall 
| 603,244 || 1,445 || 2.40 || 11,712 || 19.42
|}

==Economy==
A July 2013 ''Wall Street Journal'' article identified the [[Facebook]] initial public offering (IPO) as the cause of a change in the U.S.' national economic statistics, as San Mateo County—the home of the company—became the top wage-earning county in the country after the fourth quarter of 2012. The article revealed that the [[Bureau of Labor Statistics]] reported that the average weekly wage in the county was $3,240, which is 107% higher than the previous year: "That's the equivalent of $168,000 a year, and more than 50% higher than the next highest county, New York County (better known as Manhattan), which came in at $2,107 a week, or roughly $110,000 a year."<ref>{{cite news|title=How Facebook's IPO Created the Best-Paid County In America|url=https://blogs.wsj.com/corporate-intelligence/2013/07/02/how-facebooks-ipo-created-the-best-paid-county-in-america/|access-date=July 4, 2013|newspaper=The Wall Street Journal|date=July 2, 2013|author-first1=Scott|author-last1=Thurm|url-status=dead|archive-date=24 December 2013|archive-url=https://web.archive.org/web/20131224002434/https://blogs.wsj.com/corporate-intelligence/2013/07/02/how-facebooks-ipo-created-the-best-paid-county-in-america/}}</ref>

As of the fourth quarter of 2021, the median value of homes in San Mateo County was $1,247,070, an increase of 11% from the prior year. It ranked fourth in the U.S. for counties with highest median home value, behind [[Nantucket]], [[Manhattan]], and [[Santa Clara County, California|Santa Clara]].<ref>{{Cite web |title=County Median Home Price |url=https://www.nar.realtor/research-and-statistics/housing-statistics/county-median-home-prices-and-monthly-mortgage-payment |url-status=live |archive-url=https://archive.today/20220415015215/https://www.nar.realtor/research-and-statistics/housing-statistics/county-median-home-prices-and-monthly-mortgage-payment |archive-date=April 15, 2022 |access-date=April 14, 2022 |website=National Association of Realtors|date=January 4, 2019 }}</ref>

Additionally, San Mateo County hosts the headquarters of [[Visa Inc]], [[Sony Interactive Entertainment]], [[Electronic Arts]], [[YouTube]], [[Genentech]], [[GoPro]], and [[Gilead Sciences]], as well as a hub of venture capital firms in [[Menlo Park, California|Menlo Park]] and several other technology-related companies.

In 2016, Peninsula Clean Energy began providing electricity to 20 percent of residential customers, all municipalities, and all small- to mid-size businesses in the county, as a [[Community Choice Aggregation]] program, an alternative to [[Pacific Gas and Electric]].<ref>{{Cite web|url=http://www.mercurynews.com/2016/10/02/san-mateo-county-ditches-pge-starts-buying-cheaper-greener-energy/|title = San Mateo County ditches PG&E, starts buying cheaper, greener energy|date = October 2, 2016|website=The Mercury News}}</ref>

==Education==
[[File:Burlingame Library.JPG|thumb|right|[[Burlingame, California|Burlingame]] Public Library]]
The people of San Mateo County may use the services of [[San Mateo County Libraries]] along with the [[Peninsula Library System]] and its dozens of branches, bookmobile and [[GoLibrary|Library-a-Go-Go]] machine at the [[Millbrae BART/Caltrain station]].

The county is divided into several public school districts and is also served by the local Catholic diocese and many other private parochial and secular schools. The San Mateo County Board of Education oversees early education, special education, and the court and community schools program in the county, as well as serves as an appeal board for the adjudication of expulsion appeals, interdistrict attendance appeals, and charter schools.

Some students in San Mateo County's public schools attend outdoor education in [[La Honda]]. San Mateo Outdoor Education is a residential school that teaches major concepts of [[ecology]] via exploration of forest, pond, garden, [[tidepool]], [[wetland]], and sandy shore [[habitat]]s.<ref>{{cite web
 |url          = http://www.smcoe.k12.ca.us/outdoored/SMOLibrary/SMOLib004/SMOLib004Parents.html
 |title        = Information for Parents About Outdoor Education
 |author       = San Mateo County Office of Education
 |access-date   = June 14, 2010
|archive-url  = https://web.archive.org/web/20100316152309/http://www.smcoe.k12.ca.us/outdoored/SMOLibrary/SMOLib004/SMOLib004Parents.html
 |archive-date = March 16, 2010
|url-status     = dead
 |df           = dmy-all
}}</ref> The center's mascot is the [[banana slug]], a large yellow [[gastropod]]. The school uses songs from the famous [[Banana Slug String Band]].

===K-12 school districts===
[[File:Oceana High School (7634644054).jpg|thumb|right|[[Oceana High School]] in [[Pacifica, California|Pacifica]], part of the [[Jefferson Union High School District]]]]
They include:<ref>{{cite web|url=https://www2.census.gov/geo/maps/DC2020/PL20/st06_ca/schooldistrict_maps/c06081_san_mateo/DC20SD_C06081.pdf|title=2020 census - school district reference map: San Mateo County, CA|publisher=[[U.S. Census Bureau]]|accessdate=July 20, 2022}} - [https://www2.census.gov/geo/maps/DC2020/PL20/st06_ca/schooldistrict_maps/c06081_san_mateo/DC20SD_C06081_SD2MS.txt Text list]</ref>

; Unified
* [[Cabrillo Unified School District]]
* [[La Honda-Pescadero Unified School District]]
* [[South San Francisco Unified School District]]

; Secondary
* [[Jefferson Union High School District]]
* [[San Mateo Union High School District]]
* [[Sequoia Union High School District]]

; Elementary
{{div col|colwidth=20em}}
* [[Bayshore Elementary School District]]
* [[Belmont-Redwood Shores Elementary School District]]
* [[Brisbane Elementary School District]]
* [[Burlingame Elementary School District]]
* [[Hillsborough City Elementary School District]]
* [[Jefferson Elementary School District]]
* [[Las Lomitas Elementary School District]]
* [[Menlo Park City Elementary School District]]
* [[Millbrae Elementary School District]]
* [[Pacifica School District]]
* [[Portola Valley Elementary School District]]
* [[Ravenswood City Elementary School District]]
* [[Redwood City Elementary School District]]
* [[San Bruno Park Elementary School District]]
* [[San Carlos Elementary School District]]
* [[San Mateo-Foster City Elementary School District]]
* [[Woodside Elementary School District]]
{{div col end}}

===Private schools===
Offering secondary (6–12) education:
{{div col|colwidth=20em}}
* [[Crystal Springs Uplands School]] (K–12)
* [[Junípero Serra High School (San Mateo, California)|Junípero Serra High School]] (9–12, M)
* [[Menlo School]] (6–12)
* [[Mercy High School (Burlingame, California)|Mercy High School]] (9–12, F)
* [[Notre Dame High School (Belmont, California)|Notre Dame High School]] (9–12, F)
* [[The Nueva School]] (K–12)
* [[Pacific Bay Christian School]] (K–12)
* [[Sacred Heart Schools, Atherton|Sacred Heart]] (K–12)
* [[Silicon Valley International School Willows Campus|Silicon Valley International]] (K–12)
* [[Stanbridge Academy]] (K–12)
* [[Woodside Priory School]] (6–12)
{{div col end}}

===Higher education===
[[File:College of San Mateo (7352632808).jpg|thumb|right|Campus of [[College of San Mateo]]]]
There are three [[community college]]s in San Mateo County, all of which belong to the [[San Mateo County Community College District]]:
* [[Cañada College]] (Redwood City)
* [[College of San Mateo]] (San Mateo)
* [[Skyline College]] (San Bruno)

==Transportation==

===Major highways===
{{div col |colwidth=20em}}
*[[File:I-280 (CA).svg|25px]] [[Interstate 280 (California)|Interstate 280]]
*[[File:I-380 (CA).svg|25px]] [[Interstate 380 (California)|Interstate 380]]
*[[File:US 101 (1961 cutout).svg|25px]] [[U.S. Route 101 in California|U.S. Route 101]] ([[Bayshore Freeway]])
*[[File:California 1.svg|20px]] [[California State Route 1|State Route 1]]
*[[File:California 9.svg|20px]] [[California State Route 9|State Route 9]]
*[[File:California 35.svg|20px]] [[California State Route 35|State Route 35]] (Skyline Boulevard)
*[[File:California 82.svg|20px]] [[California State Route 82|State Route 82]] ([[El Camino Real (California)|El Camino Real]])
*[[File:California 84.svg|20px]] [[California State Route 84|State Route 84]] (Woodside Road/Bayfront Expressway/[[Dumbarton Bridge (California)|Dumbarton Bridge]])
*[[File:California 92.svg|20px]] [[California State Route 92|State Route 92]] ([[San Mateo Bridge]])
*[[File:California 109.svg|20px]] [[California State Route 109|State Route 109]]
*[[File:California 114.svg|20px]] [[California State Route 114|State Route 114]] (Willow Road)
{{div col end}}

===Public transportation===
====Rail====
[[File:Caltrain KISS leaving Millbrae station, August 2024.jpg|thumb|right|[[Caltrain]] in Millbrae]]
[[Caltrain]], the commuter rail system, connects ten cities in the county with San Francisco (to the north) and San Jose / Gilroy (to the south), running between the [[Bayshore Freeway|Highway 101]] and El Camino Real corridors for most of the way. There are [[List of Caltrain stations|13 stations in San Mateo County]], of which 12 have daily service; the ten cities with stations stretch from [[Brisbane, California|Brisbane]] on the north to [[Menlo Park, California|Menlo Park]] on the south.
;Caltrain stations in San Mateo County, from north to south:
{{div col |colwidth=15em}}
* [[Bayshore station (Caltrain)|Bayshore]]
* [[South San Francisco station (Caltrain)|South San Francisco]]
* [[San Bruno station (Caltrain)|San Bruno]]
* [[Millbrae station|Millbrae]]
* [[Broadway station (Caltrain)|''Broadway'']] (weekends)
* [[Burlingame station|Burlingame]]
* [[San Mateo station|San Mateo]]
* [[Hayward Park station|Hayward Park]]
* [[Hillsdale station (Caltrain)|Hillsdale]]
* [[Belmont station (Caltrain)|Belmont]]
* [[San Carlos station|San Carlos]]
* [[Redwood City station|Redwood City]]
* [[Menlo Park station|Menlo Park]]
{{div col end}}

[[File:Two BART trains at Millbrae station, June 2018.JPG|thumb|right|[[BART]] at [[Millbrae station]]]]
[[BART|Bay Area Rapid Transit]] (BART) trains serve [[San Francisco International Airport]] (SFO) and the northern portion of the county, paralleling El Camino Real / Mission Boulevard at [[List of Bay Area Rapid Transit stations|six stations]] between [[Daly City, California|Daly City]] and [[Millbrae, California|Millbrae]], including the station at SFO.
;BART stations in San Mateo County, from north to south:
{{div col |colwidth=15em}}
* [[Daly City station|Daly City]]
* [[Colma station|Colma]]
* [[South San Francisco station (BART)|South San Francisco]]
* [[San Bruno station (BART)|San Bruno]]
* [[San Francisco International Airport station|San Francisco International Airport]]
* [[Millbrae station|Millbrae]]
{{div col end}}

The only direct connection between Caltrain and BART is at [[Millbrae station]].

====Bus====
[[File:SamTrans Gillig Low Floor and New Flyer XD60 Xcelsior (50230070073).jpg|thumb|right|[[SamTrans]] buses in Redwood City]]
[[SamTrans]] (San Mateo County Transit District) provides local bus service within San Mateo County with some routes connecting to the [[Palo Alto Transit Center]] in Santa Clara County and [[Salesforce Transit Center]] in San Francisco. Approximately {{frac|2|3}} of all SamTrans bus routes travel along [[El Camino Real (California)|El Camino Real]], and route ECR, the primary bus route on El Camino, carries approximately 25% of SamTrans ridership.<ref>{{cite report |url=https://www.samtrans.com/media/25336/download?inline |title=El Camino Real Bus Speed and Reliability Study |date=December 2022 |publisher=San Mateo County Transit District |access-date=31 May 2024}}</ref>{{rp|1}}

Each Caltrain and BART station has connections to SamTrans routes. In addition, [[Daly City station]] is served by [[San Francisco Municipal Railway|SF Muni]] bus routes. There are many free shuttles that operate from Caltrain, BART, and Ferry stations along fixed routes to local employers during weekday commuting hours (6–10&nbsp;am and 3–7&nbsp;pm).<ref>{{cite web |url=https://commute.org/shuttles/ |title=Shuttles: Serving Commuters and Residents of San Mateo County for Over 20 Years |website=commute.org |access-date=31 May 2024}}</ref>

Overnight rail service is substituted by [[All Nighter (bus service)|All Nighter bus service]], split between SamTrans routes 397 (replacing Caltrain between San Francisco and Palo Alto via SFO) and ECR Owl (replacing BART between Daly City and SFO).<ref>{{cite web |url=https://511.org/transit/allnighter/routes |title=All Nighter Routes |website=511.org |access-date=31 May 2024}}</ref>

===Airports===
[[File:Aerial view of SFO, September 2022.JPG|thumb|right|[[San Francisco International Airport|SFO]], aerial view looking southwest]]
[[San Francisco International Airport]] is geographically located in San Mateo County, east of Highway 101 near [[San Bruno, California|San Bruno]] and [[Millbrae, California|Millbrae]], but it is owned and operated by the City and County of [[San Francisco]].

San Mateo County owns two general aviation airports: [[Half Moon Bay Airport]] and [[San Carlos Airport (California)|San Carlos Airport]].<ref>{{cite web 
| url        = http://publicworks.smcgov.org/san-mateo-county-airports
| title      = San Mateo County – Public Works – General Aviation Airports
| author     = San Mateo County Public Works
| access-date = June 14, 2010 }}</ref>

===Marine transport===
[[File:Redwood City port aerial view.jpg|thumb|right|[[Port of Redwood City]]]]
The only deepwater port in South [[San Francisco Bay]] is the [[Port of Redwood City]], situated along [[Redwood Creek, San Mateo County|Redwood Creek]], originally created as a lumber embarcadero in 1850. The San Mateo Harbor Harbor District manages the [[Pillar Point Harbor]] (on the Pacific coast side) and [[Oyster Point Marina]] (on San Francisco Bay).

The [[San Francisco Bay Ferry]] operates routes connecting the [[South San Francisco Ferry Terminal]] in Oyster Point to the [[Oakland Ferry Terminal]] in [[Jack London Square]] ([[Oakland, California|Oakland]]) and the Alameda Ferry Terminal in [[Alameda, California|Alameda]]. A free shuttle is provided to connect ferry passengers to the South San Francisco Caltrain station, via several business parks on Oyster Point.<ref>{{cite web |url=https://commute.org/route/oyster-point-ferry/ |title=OPF - Oyster Point Ferry Shuttle (SSF Ferry Terminal/Caltrain) |website=commute.org |access-date=31 May 2024}}</ref>

==Notable structures==
{{More citations needed|date=March 2016}}

There are a number of well-known structures within San Mateo County:

* [[Carolands Mansion]], Hillsborough
* [[Cow Palace]], Daly City
* [[Crystal Springs Uplands School#Uplands Mansion|Uplands Mansion]], Hillsborough
* [[Crystal Springs Reservoir]], [[municipal corporation|unincorporated]] central part of county
* [[CuriOdyssey]], San Mateo
* [[Filoli|Filoli Mansion]], Woodside
* [[The Flintstone House]], Hillsborough
* [[Notre Dame de Namur University]], Belmont, which incorporates [[Ralston Hall]]
* [[Pigeon Point Lighthouse]], Pescadero
* [[Point Montara Lighthouse]], Montara
* [[Pulgas Water Temple]], Woodside
* [[Sanchez Adobe]], Pacifica
* [[San Mateo County History Museum]], Redwood City<ref>{{Cite web|url=http://www.smdailyjournal.com/articles/lnews/2014-03-15/discovering-our-maritime-history-at-the-san-mateo-county-history-museum/1776425119785.html|archive-url=https://web.archive.org/web/20160411220234/http://www.smdailyjournal.com/articles/lnews/2014-03-15/discovering-our-maritime-history-at-the-san-mateo-county-history-museum/1776425119785.html|url-status=dead|archive-date=April 11, 2016|title=Discovering our Maritime History at the San Mateo County Historical Museum|website=San Mateo Daily Journal|access-date=March 30, 2016}}</ref>
* [[San Francisco International Airport]]
* [[Stanford Linear Accelerator Center]], Menlo Park

==Communities==

===Cities===
{{div col|colwidth=18em}}
*[[Belmont, California|Belmont]]
*[[Brisbane, California|Brisbane]]
*[[Burlingame, California|Burlingame]]
*[[Daly City, California|Daly City]]
*[[East Palo Alto, California|East Palo Alto]]
*[[Foster City, California|Foster City]]
*[[Half Moon Bay, California|Half Moon Bay]]
*[[Menlo Park, California|Menlo Park]]
*[[Millbrae, California|Millbrae]]
*[[Pacifica, California|Pacifica]]
*[[Redwood City, California|Redwood City]] (county seat)
*[[San Bruno, California|San Bruno]]
*[[San Carlos, California|San Carlos]]
*[[San Mateo, California|San Mateo]]
*[[South San Francisco, California|South San Francisco]]
{{div col end}}

===Towns===
*[[Atherton, California|Atherton]]
*[[Colma, California|Colma]]
*[[Hillsborough, California|Hillsborough]]
*[[Portola Valley, California|Portola Valley]]
*[[Woodside, California|Woodside]]

===Census-designated places===
{{div col|colwidth=18em}}
*[[Baywood Park, San Mateo County, California|Baywood Park]]
*[[Broadmoor, California|Broadmoor]]
*[[El Granada, California|El Granada]]
*[[Emerald Lake Hills, California|Emerald Lake Hills]]
*[[Highlands, California|Highlands]]
*[[Ladera, California|Ladera]]
*[[La Honda, California|La Honda]]
*[[Loma Mar, California|Loma Mar]]
*[[Montara, California|Montara]]
*[[Moss Beach, California|Moss Beach]]
*[[North Fair Oaks, California|North Fair Oaks]]
*[[Pescadero, California|Pescadero]]
*[[West Menlo Park, California|West Menlo Park]]
{{div col end}}

===Unincorporated communities===
{{div col|colwidth=22em}}
*Burlingame Hills
*Devonshire
*[[Kings Mountain, California|Kings Mountain]]
*[[Los Trancos Woods]]
*[[Menlo Oaks, California|Menlo Oaks]]
*Palomar Park
*[[Princeton-by-the-Sea, California|Princeton-by-the-Sea]]
*[[San Gregorio, California|San Gregorio]]
*[[Sky Londa, California|Sky Londa]]
{{div col end}}

===Population ranking===

The population ranking of the following table is based on the [[2020 United States census]] of San Mateo County.<ref>{{Cite web |url=https://www.census.gov/programs-surveys/decennial-census/decade.2020.html |publisher=[[United States Census Bureau]] |title=2020 U.S. Census website |access-date=December 7, 2021 }}</ref>

'''†''' ''county seat''

{| class="wikitable sortable"
|-
!Rank
!City/Town/etc.
!Municipal type
!Population (2020 Census)

|- style="background-color:#FFFACD;"
| 1
|'''[[San Mateo, California|San Mateo]]''' 
| City
| 105,661
|- style="background-color:#FFFACD;"
| 2
|'''[[Daly City, California|Daly City]]''' 
| City
| 104,901
|- style="background-color:#FFFACD;"
| 3
|'''†''' '''[[Redwood City, California|Redwood City]]''' 
| City
| 84,292
|- style="background-color:#FFFACD;"
| 4
|'''[[South San Francisco, California|South San Francisco]]''' 
| City
| 66,105
|- style="background-color:#FFFACD;"
| 5
|'''[[San Bruno, California|San Bruno]]''' 
| City
| 43,908
|- style="background-color:#FFFACD;"
| 6
|'''[[Pacifica, California|Pacifica]]''' 
| City
| 38,640
|- style="background-color:#FFFACD;"
| 7
|'''[[Foster City, California|Foster City]]''' 
| City
| 33,805
|- style="background-color:#FFFACD;"
| 8
|'''[[Menlo Park, California|Menlo Park]]''' 
| City
| 33,780
|- style="background-color:#FFFACD;"
| 9
|'''[[Burlingame, California|Burlingame]]''' 
| City
| 31,386
|- style="background-color:#FFFACD;"
| 10
|'''[[San Carlos, California|San Carlos]]''' 
| City
| 30,722
|- style="background-color:#FFFACD;"
| 11
|'''[[East Palo Alto, California|East Palo Alto]]''' 
| City
| 30,034
|- style="background-color:#FFFACD;"
| 12
|'''[[Belmont, California|Belmont]]''' 
| City
| 28,335
|- style="background-color:#FFFACD;"
|13
|'''[[Millbrae, California|Millbrae]]''' 
| City
| 23,216
|- style="background-color:#F0FFF0;"
|14
|'''[[North Fair Oaks, California|North Fair Oaks]]''' 
| CDP
| 14,027
|- style="background-color:#FFFACD;"
|15
|'''[[Half Moon Bay, California|Half Moon Bay]]''' 
| City
| 11,795
|- style="background-color:#F0F8FF;"
|16
|'''[[Hillsborough, California|Hillsborough]]''' 
| Town
| 11,387
|- style="background-color:#F0F8FF;"
|17
|'''[[Atherton, California|Atherton]]''' 
| Town
| 7,188
|- style="background-color:#F0FFF0;"
|18
|'''[[El Granada, California|El Granada]]''' 
| CDP
| 5,481
|- style="background-color:#F0F8FF;"
|19
|'''[[Woodside, California|Woodside]]''' 
| Town
| 5,309
|- style="background-color:#FFFACD;"
|20
|'''[[Brisbane, California|Brisbane]]''' 
| City
| 4,851
|- style="background-color:#F0F8FF;"
|21
|'''[[Portola Valley, California|Portola Valley]]''' 
| Town
| 4,456
|- style="background-color:#F0FFF0;"
|22
|'''[[Broadmoor, California|Broadmoor]]''' 
| CDP
| 4,411
|- style="background-color:#F0FFF0;"
|23
|'''[[Emerald Lake Hills, California|Emerald Lake Hills]]''' 
| CDP
| 4,406
|- style="background-color:#F0FFF0;"
|24
|'''[[West Menlo Park, California|West Menlo Park]]'''
| CDP
| 3,930
|- style="background-color:#F0FFF0;"
|25
|'''[[Moss Beach, California|Moss Beach]]'''
| CDP
| 3,214
|- style="background-color:#F0FFF0;"
|26
|'''[[Montara, California|Montara]]'''
| CDP
| 2,833
|- style="background-color:#F0FFF0;"
|27
|'''[[Highlands, California|Highlands]]'''
|CDP
|2,359
|- style="background-color:#F0FFF0;"
|28
|[[Baywood Park, San Mateo County, California|'''Baywood Park''']]
|CDP
|1,693
|- style="background-color:#F0FFF0;"
|29
|'''[[Ladera, California|Ladera]]'''
| CDP
| 1,557
|- style="background-color:#F0F8FF;"
|30
|'''[[Colma, California|Colma]]'''
| Town
| 1,507
|- style="background-color:#F0FFF0;"
|31
|'''[[La Honda, California|La Honda]]'''
| CDP
| 979
|- style="background-color:#F0FFF0;"
|32
|'''[[Pescadero, California|Pescadero]]'''
| CDP
| 595
|- style="background-color:#F0FFF0;"
|33
|'''[[Loma Mar, California|Loma Mar]]'''
| CDP
| 134
|}

==See also==
{{Portal|San Francisco Bay Area}}
*[[List of school districts in San Mateo County, California]]
*[[List of California Historical Landmarks#San Mateo County|List of California Historical Landmarks in San Mateo County, California]]
*[[National Register of Historic Places listings in San Mateo County, California]]
*[[Peninsula Humane Society]]
*[[Seaport Centre]]
*Telephone [[Area code 650]]
*[[Leo J. Ryan Memorial Park]]
*[[Leo J. Ryan Federal Building]]
*[[Silicon Valley]]
* [[Thomas Bones]] (1842–1929), lumberman in this area
* [[Second Harvest of Silicon Valley]]

==Notes==
{{reflist|group=note}}

==References==
{{Reflist}}

==External links==
{{commons|San Mateo County, California}}
*{{Official website}}
*[https://web.archive.org/web/20090316002153/http://smc.truebluelocal.com/ Visitors Guide from the Visitors Bureau]
*[https://smcl.org/ San Mateo County Library – 12 branches throughout the County and a bookmobile]
*[http://www.plsinfo.org/ Peninsula Library System – serving all of San Mateo County]
*[https://web.archive.org/web/20070202003728/http://www.sanmateocourt.org/midx/searchform4_tim.php Superior Court Records]
*[http://www.samcera.org SamCERA (San Mateo County Employees' Retirement Association)]
*[http://brisbanebaylands.com Brisbane Baylands Project]
*[http://www.oac.cdlib.org/ark:/13030/hb5k4005ts/?brand=oac4/ Diseño del Rancho Cañada de Guadalupe, la Visitacion y Rodeo Viejo : San Mateo Co., Ca] at [[the Bancroft Library]]

{{Geographic Location
| Centre    = San Mateo County, California
| North     = [[San Francisco County, California|San Francisco County]]
| Northeast =
| East      = [[Alameda County, California|Alameda County]]
| Southeast = [[Santa Clara County, California|Santa Clara County]]
| South     = [[Santa Cruz County, California|Santa Cruz County]]
| Southwest =
| West      = [[Pacific Ocean]]
| Northwest =
}} 
{{Cities of San Mateo County, California}}
{{San Francisco Peninsula}}
{{SF Bay Area}}
{{California}}
{{Authority control}}

[[Category:San Mateo County, California| ]]
[[Category:California counties]]
[[Category:Counties in the San Francisco Bay Area]]
[[Category:1856 establishments in California]]
[[Category:Populated places established in 1856]]
[[Category:Majority-minority counties in California]]