San Mateo County, CA
CA · Presidential Elections 1876–2024
San Mateo County, CA (California) voted D+50.3 for Kamala Harris (Democrat) in the 2024 presidential election, with Harris receiving 242,957 votes (73.5%) to 76,616 (23.18%) for Trump.
This represents a R+7.4% swing toward Republicans compared to 2020. San Mateo County is classified as a deep Democratic county. San Mateo County has voted Democratic in every presidential election since 1988. The county has a population of approximately 742,340.
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Quick Stats
Demographics
Community Profile
Religious Composition
Source: Religion Census 2020Ancestry Groups
Source: Census ACSTop reported ancestry groups (compared to national average).
Age Distribution
Employment by Industry
Census ACSPresidential Elections
Presidential Results
| Year | Democrat | Republican | Margin | Swing |
|---|---|---|---|---|
| 2024 | 73.5%(242,957) | 23.2%(76,616) | D+50.3 | R+7.4 |
| 2020 | 77.9%(291,496) | 20.2%(75,584) | D+57.7 | D+0.5 |
| 2016 | 75.7%(237,882) | 18.4%(57,929) | D+57.2 | D+10.6 |
| 2012 | 72.1%(206,085) | 25.5%(72,756) | D+46.7 | R+2.1 |
| 2008 | 73.5%(222,826) | 24.8%(75,057) | D+48.7 | D+8.5 |
| 2004 | 69.5%(197,922) | 29.3%(83,315) | D+40.2 | D+6.9 |
| 2000 | 64.3%(166,757) | 30.9%(80,296) | D+33.3 | D+2.0 |
| 1996 | 60.5%(152,304) | 29.2%(73,508) | D+31.3 | D+4.5 |
| 1992 | 54.0%(149,232) | 27.1%(75,080) | D+26.8 | D+14.0 |
| 1988 | 55.7%(141,859) | 42.9%(109,261) | D+12.8 | D+17.8 |
Source: Official state election returns via MIT Election Data + Science Lab
Presidential Margin Trend
San Mateo County, CA • 1876–2024
Senate Elections
Senate Results
| Year | Democrat | Republican | Margin | Swing |
|---|---|---|---|---|
| 2024 | 73.7%(237,186) | 26.3%(84,474) | D+47.5 | R+50.5 |
| 2018 | 98.0%(262,406) | 0.0%(0) | D+98.0 | R+4.7 |
| 2016 | 102.7%(288,662) | 0.0%(0) | D+102.7 | D+48.3 |
| 2012 | 77.2%(213,503) | 22.8%(62,979) | D+54.4 | R+0.2 |
| 2006 | 74.8%(152,082) | 20.2%(41,043) | D+54.6 | D+19.7 |
| 2000 | 64.8%(165,216) | 29.9%(76,273) | D+34.9 | D+0.6 |
| 1994 | 64.2%(136,686) | 29.9%(63,702) | D+34.3 | R+5.1 |
| 1992 | 67.3%(181,990) | 27.9%(75,470) | D+39.4 | D+33.5 |
| 1988 | 51.1%(125,724) | 45.2%(111,187) | D+5.9 | D+8.1 |
| 1982 | 47.0%(98,862) | 49.2%(103,493) | R+2.2 | D+0.8 |
Source: Official state election returns via MIT Election Data + Science Lab
Governor Elections
Governor Results
| Year | Democrat | Republican | Margin | Swing |
|---|---|---|---|---|
| 2022 | 75.0%(185,599) | 25.0%(61,918) | D+50.0 | R+0.5 |
| 2018 | 75.2%(213,282) | 24.8%(70,242) | D+50.5 | D+0.0 |
| 2014 | 75.2%(120,280) | 24.8%(39,615) | D+50.4 | D+15.9 |
| 2010 | 65.7%(145,970) | 31.1%(69,212) | D+34.5 | D+34.2 |
| 2006 | 47.4%(97,092) | 47.1%(96,478) | D+0.3 | R+27.8 |
| 2002 | 58.0%(99,803) | 29.9%(51,497) | D+28.1 | R+11.9 |
| 1998 | 68.4%(142,144) | 28.5%(59,249) | D+39.9 | D+38.3 |
| 1994 | 49.2%(106,391) | 47.6%(102,989) | D+1.6 | R+13.4 |
| 1990 | 55.4%(109,963) | 40.5%(80,253) | D+15.0 | D+40.6 |
| 1986 | 36.2%(71,329) | 61.8%(121,910) | R+25.7 | R+29.8 |
Source: Official state election returns via MIT Election Data + Science Lab