Marin County, California
Located in California, Marin County has a population of 257,969 residents and a median age of 47.4 years, making it the #279 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 8.3%. The median home value is $1.5M, and the median household income is $149,091, which is 98% above the national median.
Demographics
Marin County has a population of 257,969, making it the #279 most populous county in the US. The median age is 47.4 years, which is 21.9% above the national median.
Population Trend
Rankings →Year-over-Year Population Growth
Age & Sex Distribution
Race & Ethnicity
Nativity
Geographic Mobility (Past Year)
Economy
The median household income in Marin County is $149,091, ranking #7 out of 3,222 counties — 98.4% above the national median. The poverty rate is 8.3% and unemployment stands at 6.1%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Marin County is $1.5M (+434.7% vs national). Renters pay a median of $2,668/mo and the homeownership rate is 64.7%.
Median Home Value Trend
Rankings →Household Type
Education
In Marin County, 61.1% of adults age 25+ hold a bachelor's degree or higher, which is 81.4% above the national average, ranking #20 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Marin County is 84.3 years. 10.6% of adults report poor or fair health and 5.1% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
7.5% of adults in Marin County smoke , 23.5% are obese , and 25.1% report excessive drinking. The drug overdose death rate is 23.7 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Marin County is 1.9 per 100,000 and the suicide rate is 13.5 per 100,000. Motor vehicle deaths occur at a rate of 5.6 per 100,000.
Homicide Rate Trend
Families & Children
8.1% of children in Marin County live in poverty and the infant mortality rate is 1.6 per 1,000 live births. The teen birth rate is 4.3 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Marin County is 84.0%. The mean commute time is 30.6 min, which is 10.8% above the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, Marin County voted Democratic with a margin of 63.9%. The vote was 80.6% Dem / 16.7% Rep. Compared to 2020, the margin shifted 2.6 toward Republicans .
Vote Share Over Time
About Marin County, California
Marin County, California has a total population of 257,969, making it the 279th most populous county in the United States. The median age in Marin County is 47.4 years, which is 21.9% above the national median of 38.9 years.
The median household income in Marin County is $149,091, which ranks #7 of 3,222 counties nationwide. This is 98.4% above the national median of $75,149. The poverty rate is 8.3%, lower than the national rate of 12.6%. The unemployment rate stands at 6.1%.
The median home value in Marin County is $1.5M, 434.7% above the national median. Renters in Marin County pay a median gross rent of $2,668 per month. The homeownership rate is 64.7%, compared to the national rate of 64.4%.
In Marin County, 61.1% of residents aged 25 and older hold a bachelor's degree or higher, 81.4% above the national average of 33.7%. Health insurance coverage stands at 96.2% of the population. The average commute time for workers is 30.6 min.
Marin County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 65.1% of the population, followed by Hispanic or Latino (19.5%) and Asian (non-Hispanic) (6.1%).
All data for Marin County, California comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates. These figures are estimates based on survey sampling and are subject to margin of error. For the most detailed and up-to-date data, visit the Census Bureau's official data portal.