Data as of October 18, 2026 · refreshed automatically from the official California voter file
Marin County, CA has 173,257 active registered voters — 12.4% Republican, 61.6% Democratic, and 19.5% with no party affiliation, as of October 2026.
Party registration
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 41207-B | 549 | 449 | 81.79% |
| 2 | 41251-A | 491 | 397 | 80.86% |
| 3 | 41216-H | 492 | 386 | 78.46% |
| 4 | 10920-B | 780 | 600 | 76.92% |
| 5 | 10903-B | 595 | 455 | 76.47% |
| 6 | 20439 | 709 | 539 | 76.02% |
| 7 | 10929 | 861 | 654 | 75.96% |
| 8 | 20303 | 780 | 592 | 75.9% |
| 9 | 41211-B | 843 | 639 | 75.8% |
| 10 | 41215-B | 632 | 479 | 75.79% |
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 Marin County voted for president
Election results are public records.
Marin County at a glance.
Marin County had an estimated 256,400 residents in July 2024, the 26th most populous of California's 58 counties, down 2.3% since the 2020 census. Of those, 208,562 are 18 or older, the voting-age population, and 25.0% are 65 or older. Its 173,257 active registered voters equal about 83.1% of that voting-age population.
It covers 520 square miles of land (493 people per square mile), and 26.1% of residents live outside any incorporated city or town. The largest cities and towns are San Rafael (59,961), Novato (52,311), Mill Valley (13,904), Larkspur (12,807) and San Anselmo (12,645). The American Community Survey (2020-2024) puts it at a median age of 47.4, a median household income of $149,091, 61.1% of adults 25 and older holding a bachelor's degree or higher and 64.7% of occupied homes owned by the people living in them.
In 2024, 144,113 votes were cast for president, about 69.1% of the voting-age population; the Democratic ticket took 80.6% and the Republican ticket 16.7%. The two-party margin moved from D+57.8 in 2008 to D+63.9 in 2024.
- Population (2024 estimate)
- 256,400
- Population (2020 census base)
- 262,325
- Voting-age population (18+)
- 208,562
- Active voters per 100 adults
- 83.1
- Residents 65 and older
- 25.0%
- People per square mile
- 493
- Living outside incorporated places
- 26.1%
- Land area
- 520 sq mi
- Median age
- 47.4
- Median household income
- $149,091
- Adults 25+ with a bachelor's degree
- 61.1%
- Owner-occupied homes
- 64.7%
Largest cities and towns
- San Rafael 59,961
- Novato 52,311
- Mill Valley 13,904
- Larkspur 12,807
- San Anselmo 12,645
Presidential vote, 2008–2024
| Year | Democratic | Republican | Margin | Votes cast |
|---|---|---|---|---|
| 2024 | 80.6% | 16.7% | D+63.9 | 144,113 |
| 2020 | 82.3% | 15.8% | D+66.5 | 155,801 |
| 2016 | 78.8% | 15.9% | D+62.9 | 109,941 |
| 2012 | 74.0% | 23.5% | D+50.5 | 99,286 |
| 2008 | 78.0% | 20.2% | D+57.8 | 140,197 |
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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