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California·CA·FIPS 06081
San Mateo County
Voted Democratic in 2024 · 330,510 votes cast
About San Mateo County
San Mateo County, officially the County of San Mateo, is a county located in the U.S. state of California. As of the 2020 United States census, the population was 764,442. Redwood City is the county seat, the third-most populated city in the county after Daly City and San Mateo.
Read more on Wikipedia →Total Votes (2024)
330,510
Winner Margin
D+50.3
Turnout Change
-11.7%
2020→2024 Swing
R+7.4
2024 Presidential Results
All candidates · San Mateo County, California
Kamala D Harris(Democrat)
73.5%242,957
Won by 166,341 votes
Donald J Trump(Republican)
23.2%76,616
Other(Other)
2.8%9,250
Chase Oliver(Libertarian)
0.5%1,687
Margin History
Red = Republican, Blue = Democratic
2024D+50.3
2020D+57.7
2016D+57.2
🔴
Swung Right in 2024
San Mateo County shifted 7.4 points toward Republicans compared to 2020. Voter turnout decreased by 11.7%.
What does San Mateo County really think?
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Election data: MIT Election Data Science Lab, Harvard Dataverse (CC BY 4.0)