San Mateo County, California
AkashicSan Mateo County, CAHarrisD+50.3
2024 precinct map of San Mateo CountyPrecinct-level 2024 presidential results for San Mateo County, with each precinct boundary colored by Democratic-vs-Republican margin, and gold where an independent or third-party candidate carried the precinct.
How it voted
Share of the 2024 vote
| Kamala Harris ✓Democratic | 73.5% | 242,957 |
|---|---|---|
| Donald TrumpRepublican | 23.2% | 76,616 |
| Jill SteinGreen | 1.2% | 4,119 |
Harris +50Trump +50
295 precincts · 330,510 votes. Hover any precinct for its result.
The precinct map shows the 2024 presidential vote; the timeline scrubs the county’s overall result across 1876–2024.
38 presidential elections
| Year | Won | Democratic | Republican | Other | Margin | Total |
|---|---|---|---|---|---|---|
| D | 73.5%Harris242,957 | 23.2%Trump76,616 | 1.2%Stein4,119 | 330,510 | ||
| D | 77.9%Biden291,496 | 20.2%Trump75,584 | 0.9%Jorgensen3,554 | 374,251 | ||
| D | 75.7%Clinton237,882 | 18.4%Trump57,929 | 3.0%Johnson9,464 | 314,384 | ||
| D | 72.1%Obama206,085 | 25.5%Romney72,756 | 1.0%Johnson2,926 | 285,720 | ||
| D | 73.5%Obama222,826 | 24.7%McCain75,057 | 1.8%Nader5,409 | 303,292 | ||
| D | 69.5%Kerry197,922 | 29.2%Bush83,315 | 1.3%Badnarik3,620 | 284,857 | ||
| D | 64.3%Gore166,757 | 31.0%Bush80,296 | 4.0%Nader10,433 | 259,399 | ||
| D | 60.6%Clinton152,304 | 29.2%Dole73,508 | 6.0%Perot15,047 | 251,532 | ||
| D | 54.0%Clinton149,232 | 27.2%Bush75,080 | 18.3%Perot50,465 | 276,508 | ||
| D | 55.7%Dukakis141,859 | 42.9%Bush109,261 | 1.3%Paul3,360 | 254,480 | ||
| R | 46.9%Mondale122,268 | 51.9%Reagan135,185 | 1.2%Bergland3,178 | 260,631 | ||
| R | 36.6%Carter87,335 | 48.8%Reagan116,491 | 14.6%Anderson34,811 | 238,637 | ||
| R | 44.4%Carter102,896 | 50.6%Ford117,338 | 5.0%Macbride11,507 | 231,741 | ||
| R | 42.8%McGovern109,745 | 52.8%Nixon135,377 | 4.4%Schmitz11,175 | 256,297 | ||
| D | 47.2%Humphrey106,519 | 43.7%Nixon98,654 | 9.1%Wallace20,495 | 225,668 | ||
| D | 64.3%Johnson140,978 | 35.5%Goldwater77,916 | 0.1%Hass297 | 219,191 | ||
| R | 48.0%Kennedy97,154 | 51.7%Nixon104,570 | 0.3%Byrd528 | 202,252 | ||
| R | 38.8%Stevenson63,637 | 61.0%Eisenhower100,049 | 0.1%Andrews217 | 163,903 | ||
| R | 36.5%Stevenson50,802 | 63.1%Eisenhower87,780 | 0.5%Hallinan640 | 139,222 | ||
| R | 39.7%Truman34,215 | 56.7%Dewey48,909 | 3.6%Thurmond3,148 | 86,272 | ||
| D | 50.6%Roosevelt34,594 | 49.1%Dewey33,590 | 0.2%Thomas158 | 68,342 | ||
| D | 52.4%Roosevelt29,831 | 46.6%Willkie26,539 | 1.0%Thomas581 | 56,951 | ||
| D | 65.7%Roosevelt27,087 | 33.1%Landon13,650 | 1.2%Lemke511 | 41,248 | ||
| D | 56.4%Roosevelt19,094 | 39.7%Hoover13,442 | 4.0%Thomas1,343 | 33,879 | ||
| R | 40.0%Smith9,755 | 58.9%Hoover14,360 | 1.1%Thomas277 | 24,392 | ||
| R | 5.2%Davis771 | 55.3%Coolidge8,126 | 39.5%La Follette5,805 | 14,702 | ||
| R | 19.2%Cox1,958 | 70.5%Harding7,205 | 10.3%Debs1,054 | 10,217 | ||
| R | 43.1%Wilson4,485 | 50.0%Hughes5,207 | 6.9%Benson719 | 10,411 | ||
| O | 46.5%Wilson3,246 | 0.0%Taft0 | 53.5%Roosevelt3,739 | 6,985 | ||
| R | 28.9%Bryan1,314 | 62.9%Taft2,865 | 8.2%Debs375 | 4,554 | ||
| R | 27.1%Parker851 | 68.5%Roosevelt2,146 | 4.4%Debs138 | 3,135 | ||
| R | 35.0%Bryan914 | 63.0%McKinley1,645 | 2.0%Woolley52 | 2,611 | ||
| R | 37.5%Bryan987 | 61.1%McKinley1,607 | 1.4%Palmer36 | 2,630 | ||
| R | 47.4%Cleveland1,020 | 50.6%Harrison1,088 | 2.0%Weaver44 | 2,152 | ||
| R | 46.3%Cleveland980 | 53.0%Harrison1,121 | 0.8%Fisk16 | 2,117 | ||
| R | 43.7%Cleveland750 | 55.3%Blaine950 | 1.0%Butler17 | 1,717 | ||
| R | 48.3%Hancock720 | 51.0%Garfield760 | 0.7%Weaver10 | 1,490 | ||
| R | 44.4%Tilden696 | 55.6%Hayes871 | 0.0% | 1,567 |
presidential history
Presidential margin, 1876–2024
Democratic minus Republican, by election
| Year | Margin (D minus R) |
|---|---|
| 1876 | −11.2% |
| 1880 | −2.7% |
| 1884 | −11.6% |
| 1888 | −6.7% |
| 1892 | −3.2% |
| 1896 | −23.6% |
| 1900 | −28.0% |
| 1904 | −41.3% |
| 1908 | −34.1% |
| 1912 | +46.5% |
| 1916 | −6.9% |
| 1920 | −51.4% |
| 1924 | −50.0% |
| 1928 | −18.9% |
| 1932 | +16.7% |
| 1936 | +32.6% |
| 1940 | +5.8% |
| 1944 | +1.5% |
| 1948 | −17.0% |
| 1952 | −26.6% |
| 1956 | −22.2% |
| 1960 | −3.7% |
| 1964 | +28.8% |
| 1968 | +3.5% |
| 1972 | −10.0% |
| 1976 | −6.2% |
| 1980 | −12.2% |
| 1984 | −5.0% |
| 1988 | +12.8% |
| 1992 | +26.8% |
| 1996 | +31.3% |
| 2000 | +33.3% |
| 2004 | +40.2% |
| 2008 | +48.7% |
| 2012 | +46.7% |
| 2016 | +57.2% |
| 2020 | +57.7% |
| 2024 | +50.3% |
DemocraticRepublican
voter registration
Registered voters
By party of registration, over time
DemocraticRepublicanUnaffiliatedOther parties
| Year | Total registered | Democratic | Republican | Unaffiliated | Other |
|---|---|---|---|---|---|
| 2022 | 430,809 | 242,057 | 60,027 | 105,769 | 22,956 |
| 2024 | 436,700 | 244,724 | 64,166 | 103,418 | 24,392 |
Source: California Secretary of State
San Mateo County sits between San Francisco and Silicon Valley, combining high housing costs and a highly educated workforce with some of the most consistent Democratic margins on the California coast.
Across the recorded series it reached a Democratic high of 57.7 points in 2020 and a Republican high of 51.4 points in 1920. Between 2020 and 2024 the county moved 7.4 points toward the Republican candidate; the 2024 margin was 50.3 points.
A population of 742,340, a 35% non-Hispanic-white share, and a median household income of $158,855 describe the county. The county's voting pattern over the last decade is most similar to that of Marin County and Richmond city.
Most similar counties
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All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
San Mateo County, California. Akashic. https://akashic.app/county/06081/. Accessed May 20, 2026. License: CC BY 4.0.
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Cities & towns in San Mateo County
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Frequently asked questions
How did San Mateo County, California vote in 2024?
In 2024, San Mateo County, California voted Democratic by 50.3 points (D+50.3), carried by the Democratic candidate. Out of 330,510 votes cast, 242,957 went Democratic and 76,616 went Republican.
When did San Mateo County, California last vote Republican?
The most recent presidential election in which San Mateo County, California voted Republican was 1984.
How many people live in San Mateo County, California?
San Mateo County, California has a population of 742,340 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in San Mateo County, California?
Median household income in San Mateo County, California is $158,855 — above the national median of $80,734. The California state median is $99,122.
What is the political history of San Mateo County, California?
Akashic tracks 38 presidential elections in San Mateo County, California from 1876 to 2024. Of those, 16 went Democratic and 21 went Republican.