San Mateo County, California Demographics 2026

Population Overview

San Mateo County is located in California with a total population of 745,100. It is the 15th most populous county out of 58 in California.

Age Demographics

The median age in San Mateo County is 40.6 years. This is 8% higher than the state median of 37.6 years.

Economy, Income & Housing

The median household income in San Mateo County is $156,000. This is 62% higher than the state median of $96,334. Compared to the national median of $78,538, household income here is 99% higher. The poverty rate stands at 6.5%. This is 46% lower than the state poverty rate of 12.0%. The unemployment rate is 4.5%. This is 30% lower than the state rate of 6.4%. The median home value is $1,494,500. Housing costs are 115% higher than the state median of $695,400. The home-value-to-income ratio of 9.6x suggests that housing affordability is a significant concern for many residents. 59.1% of occupied housing units are owner-occupied. This homeownership rate is 6% higher than the state average of 55.8%.

Race & Ethnicity

San Mateo County is a highly diverse community where no single racial or ethnic group constitutes a majority of the population. Asian residents account for 30.5%. The Black or African American population (2.1%) is well below the state average of 5.3%. The Asian population is significantly higher than the state average (30.5% vs 15.0%).

Education

53.1% of residents aged 25 and older hold a bachelor's degree or higher. This places San Mateo County in the top 10% of all cities in the state for educational attainment. This is 45% higher than the state rate of 36.5%. Nationally, 35.0% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 90.3%. Notably, 23.9% of adults hold a graduate or professional degree, indicating a highly educated workforce.