Presidential elections · 2000–2024
San Mateo County, CA — Presidential Election Results (2000–2024)
In 2024, San Mateo County, California voted for Kamala D. Harris (Democratic) by D+50.3 — 242,957 Democratic to 76,616 Republican of 330,510 votes cast. From 2020 to 2024 it shifted 7.4 points toward Republicans. That makes it 30.2 points more Democratic than California overall (D+20.1).
Data: MIT Election Data & Science Lab, Harvard Dataverse.
Margin by election, 2000–2024
Democratic minus Republican, in points of all votes cast — blue bars Democratic, red Republican.
Every election in San Mateo County
| Year | Democratic | Republican | Other | Dem share | Rep share | Margin |
|---|---|---|---|---|---|---|
| 2024 | 242,957 | 76,616 | 10,937 | 73.5% | 23.2% | D+50.3 |
| 2020 | 291,496 | 75,584 | 7,171 | 77.9% | 20.2% | D+57.7 |
| 2016 | 237,882 | 57,929 | 18,573 | 75.7% | 18.4% | D+57.2 |
| 2012 | 206,085 | 72,756 | 6,879 | 72.1% | 25.5% | D+46.7 |
| 2008 | 222,826 | 75,057 | 5,409 | 73.5% | 24.7% | D+48.7 |
| 2004 | 197,922 | 83,315 | 2,840 | 69.7% | 29.3% | D+40.3 |
| 2000 | 166,757 | 80,296 | 12,346 | 64.3% | 31.0% | D+33.3 |
San Mateo County presidential elections — FAQ
Who carried San Mateo County in the 2024 presidential election?+
Kamala D. Harris (Democratic) carried San Mateo County, California in 2024 by D+50.3, with 330,510 votes cast. Data: MIT Election Data & Science Lab.
How did San Mateo County shift between 2020 and 2024?+
San Mateo County shifted 7.4 points toward Republicans between 2020 (D+57.7) and 2024 (D+50.3).
Is San Mateo County more Democratic or Republican than California overall?+
In 2024, San Mateo County went D+50.3 while California overall went D+20.1 — 30.2 points more Democratic than the state.
Where does this election data come from?+
County-level presidential returns (2000–2024) come from the MIT Election Data and Science Lab (MEDSL), published on the Harvard Dataverse. pumsdata is an independent product that makes the data easy to map and compare, and is not affiliated with MEDSL or Harvard.