Marin County, California Demographics 2026

Population Overview

Marin County is located in California with a total population of 257,969. It is the 26th most populous county out of 58 in California. The county encompasses 31 Census-designated places.

Age Demographics

The median age in Marin County is 47.4 years. This is 25% higher than the state median of 37.9 years. 10.7% of residents are 75 or older, suggesting a significant retirement-age population with implications for healthcare services and senior housing.

Economy, Income & Housing

The median household income in Marin County is $149,091. This is 50% higher than the state median of $99,122. It is also 85% higher than the national median of $80,734. The poverty rate stands at 8.3%. This is 31% lower than the state poverty rate of 12.0%. The unemployment rate is 6.1%. This is 8% lower than the state rate of 6.6%. The median home value is $1,507,300. Housing costs are 105% higher than the state median of $734,700. The home-value-to-income ratio of 10.1x suggests that housing affordability is a significant concern for many residents. 64.7% of occupied housing units are owner-occupied. This homeownership rate is 16% higher than the state average of 55.9%.

Race & Ethnicity

The largest racial or ethnic group in Marin County is White (non-Hispanic), making up 65.0% of the population. Hispanic or Latino residents account for 19.5%. The White (non-Hispanic) population is significantly higher than the state average (65.0% vs 33.8%). The Black or African American population (2.1%) is well below the state average of 5.2%. The Hispanic or Latino population (19.5%) is well below the state average of 40.2%. The Asian population (6.1%) is well below the state average of 15.3%.

Education

61.1% of residents aged 25 and older hold a bachelor's degree or higher. This places Marin County in the top 10% of all counties in the state for educational attainment. This is 65% higher than the state rate of 37.1%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 92.8%. Notably, 27.6% of adults hold a graduate or professional degree, indicating a highly educated workforce.

Data Sources & Methodology

All figures for Marin County come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, with comparisons drawn against California and national averages from the same dataset. See our methodology page for how each metric is defined, or data.census.gov for official tables with margins of error.