County record · fips 06081 · California
San MateoCA
Democratic ×10 since 1988all 40 elections, 1868–2024
The Long Record
40 elections against the California and national vote
2024 result
D+52.1
won by Democrats
Record since first cycle
18–22
Dem–Rep two-party wins
Voted with the winner
27/40
68% of its elections
Closest election
1944
D+1.5
this countyCalifornianational (official)dot colour = two-party winner · hollow = tie or unknown total · click a dot to open that election
The Biggest Swings
Cycle-over-cycle change in the two-party margin, in points
| Election | Swing | Toward |
|---|---|---|
| 1912 | +136.7 pts | Democrats |
| 1916 | -107.0 pts | Republicans |
| 1872 | +71.8 pts | Democrats |
| 1928 | +64.1 pts | Democrats |
| 1876 | -62.8 pts | Republicans |
Who Lives Here
Census & ACS county profile, 2024
Population
742,340
College (BA+)
54%
Median income
$158,855
2024 dollars
Non-white
65%
Rural
2%
Age 65+
18%
Interpolated between Census/ACS anchors; income CPI-deflated to 2024. Demographics begin in 2000 — earlier cycles have returns only.