Data as of November 4, 2026 · refreshed automatically from the official California voter file
San Diego County, CA has 2,019,444 active registered voters — 27.2% Republican, 40.7% Democratic, and 24.3% with no party affiliation, as of November 2026.
Party registration
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 408670.0 | 855 | 706 | 82.57% |
| 2 | 106440.0 | 467 | 371 | 79.44% |
| 3 | 406350.0 | 598 | 462 | 77.26% |
| 4 | 105040.0 | 480 | 364 | 75.83% |
| 5 | 450080.0 | 481 | 363 | 75.47% |
| 6 | 105000.0 | 576 | 434 | 75.35% |
| 7 | 501190.0 | 400 | 299 | 74.75% |
| 8 | 406360.0 | 520 | 387 | 74.42% |
| 9 | 406340.0 | 477 | 355 | 74.42% |
| 10 | 412800.0 | 587 | 427 | 72.74% |
Supervoters are active registered voters who cast a ballot in at least 3 of the last 4 November general elections (2018–2024). Percentages are precinct totals from the official state voter file — no individual voter information is shown. Precincts with fewer than 400 active voters are excluded.
How San Diego County voted for president
Election results are public records.
San Diego County at a glance.
San Diego County had an estimated 3,298,799 residents in July 2024, the second most populous of California's 58 counties, essentially unchanged since the 2020 census. Of those, 2,627,206 are 18 or older, the voting-age population, and 16.3% are 65 or older. Its 2,019,444 active registered voters equal about 76.9% of that voting-age population.
It covers 4,210 square miles of land (784 people per square mile), and 15.3% of residents live outside any incorporated city or town. The largest cities and towns are San Diego (1,404,452), Chula Vista (278,546), Oceanside (170,941), Escondido (148,847) and Carlsbad (113,575). The American Community Survey (2020-2024) puts it at a median age of 37.3, a median household income of $106,268, 43.2% of adults 25 and older holding a bachelor's degree or higher and 54.6% of occupied homes owned by the people living in them.
In 2024, 1,477,786 votes were cast for president, about 56.2% of the voting-age population; the Democratic ticket took 56.9% and the Republican ticket 40.1%. The two-party margin moved from D+10.2 in 2008 to D+16.8 in 2024.
- Population (2024 estimate)
- 3,298,799
- Population (2020 census base)
- 3,298,647
- Voting-age population (18+)
- 2,627,206
- Active voters per 100 adults
- 76.9
- Residents 65 and older
- 16.3%
- People per square mile
- 784
- Living outside incorporated places
- 15.3%
- Land area
- 4,210 sq mi
- Median age
- 37.3
- Median household income
- $106,268
- Adults 25+ with a bachelor's degree
- 43.2%
- Owner-occupied homes
- 54.6%
Largest cities and towns
- San Diego 1,404,452
- Chula Vista 278,546
- Oceanside 170,941
- Escondido 148,847
- Carlsbad 113,575
Presidential vote, 2008–2024
| Year | Democratic | Republican | Margin | Votes cast |
|---|---|---|---|---|
| 2024 | 56.9% | 40.1% | D+16.8 | 1,477,786 |
| 2020 | 60.2% | 37.5% | D+22.7 | 1,601,722 |
| 2016 | 56.1% | 38.2% | D+17.9 | 1,011,651 |
| 2012 | 51.5% | 46.4% | D+5.1 | 928,256 |
| 2008 | 54.1% | 43.9% | D+10.2 | 1,231,047 |
Sources: U.S. Census Bureau Vintage 2024 population estimates and 2024 Gazetteer; American Community Survey 2020–2024 5-year estimates; certified county presidential returns. Growth, density and turnout are simple arithmetic on those figures.
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