San Mateo County, CA — Elections & Voting
Presidential election results and party lean trends
Election Overview
Source: San Mateo County (2024)2024 Winner
Democrat
Dem Votes
242,957
73.5%
GOP Votes
76,616
23.2%
Total Votes
330,510
Margin
D+50.3%
Shift from 2020
R+7.4pp
vs prior election
📊Election Results by Year
2016–2024📈Partisan Lean Trend
D+50.3%Election History
Source: County-Level Election Results| Year | Dem Votes | GOP Votes | Total | Dem % | GOP % | Margin |
|---|---|---|---|---|---|---|
| 2024 | 242,957 | 76,616 | 330,510 | 73.5% | 23.2% | D+50.3 |
| 2020 | 291,410 | 75,563 | 374,138 | 77.9% | 20.2% | D+57.7 |
| 2016 | 219,580 | 53,731 | 287,499 | 76.4% | 18.7% | D+57.7 |
In the 2024 presidential election, San Mateo County recorded 330,510 total votes. Democrats won the county with 73.5% of the vote compared to 23.2% for Republicans, a margin of D+50.3%. Compared to 2020, the margin shifted R+7.4pp from the previous election. Since 2016, San Mateo County has shifted 7.4 percentage points toward Republicans.