Marin County, California Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
Marin County, CA Population Density Map and Area Scores
Area Score
Health, income and education, each graded from F to A+. Explore interactive maps for deeper analysis.
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A+
Health Top gradeAmong the top 5 healthiest counties in California
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A+
Income Top gradeWealthiest county in California
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A+
Education Top gradeBest educated county in California
Source: Map AI Methodology
Population: density and quick facts
| Metric | Marin County | California Avg | U.S. Average |
|---|---|---|---|
| Population | 257,932 | 39,245,658 | 337,468,954 |
| Population density (per sq mi) | 311.7 | 239.4 | 86.4 |
| Population growth (%/yr) | -0.21% | 0.19% | 0.59% |
| Median age | 48.8 | 35.5 | 37.3 |
| Households | 101,954 | 13,531,619 | 130,235,071 |
Population in Marin County grew by 2.5% from 2009 to 2024, reaching 257,932 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in Marin County is Gen X, aged 45–60, at 25.1% of residents. That is 5.3 points above California as a whole.
- Gen Z 13–28 42,883 16.6% -5.1 pts
- Millennials 29–44 45,456 17.6% -6.0 pts
- Gen X 45–60 64,863 25.1% +5.3 pts
- Boomers 61–79 55,517 21.5% +6.3 pts
Residents by birth cohort, from the 2025 age distribution. The right-hand figure is how far each cohort's share sits above or below California, in percentage points. Children younger than Gen Z and the generations before the Boomers are counted in the population but not shown here, so these shares do not add up to 100%.
Male and female share
Women are 50.8% of the people living in Marin County and men 49.2%.
- Women 50.8% California 49.9%
- Men 49.2% California 50.1%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in Marin County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
Marin County has a the economy index of A+, which means it is exceptionally prosperous.
| Metric | Marin County | California Avg | U.S. Average |
|---|---|---|---|
| Median household income | $149,382 | $99,161 | $80,455 |
| Income growth (%/yr) | 5.18% | 5.57% | 4.80% |
| Unemployment rate | 6.1% | 6.6% | 5.2% |
The median household income in Marin County is about 51% higher than in California.
Housing
| Metric | Marin County | California Avg | U.S. Average |
|---|---|---|---|
| Median home price | $737,594 | $650,794 | $248,835 |
| Median rent | $2,667 | $2,036 | $1,407 |
| Homeownership rate | 64.6% | 55.9% | 65.2% |
The median home price in Marin County is about 23.0 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $2,667 per month for that long.
Commute Time & Mobility
Commuters in Marin County spend about 46 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 190 hours, about 7.9 full days, spent commuting.
| Metric | Marin County | California Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 22.8 | 23.5 | 22.4 |
| Round-trip commute (min) | 45.7 | 47.0 | 44.8 |
| Yearly time spent (hours) | 190 | 196 | 187 |
| Estimated yearly cost | $5,901 | $6,065 | $5,790 |
| Work from home | 31.4% | 17.2% | 15.0% |
| Highway traffic (vehicles/day) | 21,322 | 16,509 | 8,813 |
| Local road traffic (vehicles/day) | 2,135 | 2,449 | 1,355 |
Fastest commutes among counties in
California:
Inyo County (11.1 min), Mono County (12.0 min), Del Norte County (12.1 min).
Slowest:
Alpine County (31.3 min), San Benito County (31.2 min), Contra Costa County (31.0 min).
The average commute time in Marin County is about the same as in California.
Estimated yearly cost applies a single national wage rule of thumb (U.S. Bureau of Labor Statistics average hourly earnings), not a measurement of wages in this area. Traffic volume figures come from proprietary Ticon and TrafficZoom data.
Education & Households
Marin County has a education index of A+, which means it is exceptionally educated.
| Metric | Marin County | California Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 57.4% | 33.0% | 31.6% |
| Average household size | 2.43 | 2.84 | 2.53 |
Highest education index among counties in
California:
Marin County (0.5), San Francisco County (0.4), Santa Clara County (0.4).
Lowest:
Colusa County (0.2), Merced County (0.2), Glenn County (0.2).
Health
Marin County has a health index of A+, which means it is exceptionally healthy.
| Metric | Marin County | California Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 83.4 | 79.6 | 78.3 |
| Self-rated poor health | 10.8% | 16.4% | 16.3% |
| Smokers | 9.1% | 13.9% | 19.0% |
Highest health index among counties in
California:
San Francisco County (0.8), San Mateo County (0.8), Santa Clara County (0.8).
Lowest:
Lake County (0.8), Imperial County (0.8), Tulare County (0.8).
Marin County, CA Compared With Nearby Counties
Marin County, CA is the 5th largest of the 6 counties compared here, 257,932 residents against a local median of 733,246. Marin County, CA's median home price, at $737,594, runs 18% below the $902,338 typical of the counties around it.
Median household income tells the same story from another angle: $149,382 against a local median of $127,405, 17% above it. The one measure here that carries a verdict is median household income, and at 17% above the local median it puts Marin County, CA at the better end of the local range. The counties themselves spread $1,081,713 on median home price, so Marin County, CA sits at one end of an already wide local range rather than apart from it. Marin County, CA has the 4th highest median home price of the 6 areas compared here.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| Marin County, CA | 257,932 | $149,382 #2/6 | $737,594 #4/6 | 22.8 min #3/6 |
| San Francisco County, CA | 829,818 | $140,554 | $1,276,188 | 28.7 min |
| Sonoma County, CA | 485,012 | $105,553 | $667,194 | 20.5 min |
| Napa County, CA | 134,769 | $112,778 | $902,338 | 20.3 min |
| San Mateo County, CA | 733,246 | $159,405 | $1,744,985 | 23.2 min |
| Contra Costa County, CA | 1,163,035 | $127,405 | $663,272 | 31.0 min |
Frequently Asked Questions
Common questions about Marin County, California.
What is the population of Marin County, California?
About 257,932 people live in Marin County, California, in 101,954 households of 2.4 people on average. The median age is 48.8, so residents are older than the U.S. median of 37.3 by about 11 years.
How densely populated is Marin County, California?
Averaged over its land area, Marin County, California has 312 people per square mile, a density typical of a mix of suburbs, small towns and farmland. That is about 3.6 times the U.S. average of 86.
How affordable is housing in Marin County, California?
The median home costs 4.9 times the median household income ($737,594 against $149,382), compared with 3.1 times nationally. A ratio of about 3 is traditionally considered affordable. Median rent of $2,667 a month takes about 21% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
How educated are people in Marin County, California?
57.4% of adults in Marin County, California hold a bachelor's degree or higher (about 6 in 10), well above the U.S. share of 31.6%.
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