San Mateo County, California Demographics 2026
San Mateo County, California has a population of 742,340, the 15th most populous county in California. The median household income is $158,855 and the median home value is $1,559,600. The poverty rate is 6.7%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
San Mateo County Quick Facts
How San Mateo County Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 745,100 | 742,340 | -0.4% |
| Median household income | $156,000 | $158,855 | +1.8% |
| Median home value | $1,494,500 | $1,559,600 | +4.4% |
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
This community is exceptionally diverse, with no single racial or ethnic group dominating the population.
State average: 70 | National average: 61
Education
Educational Attainment (Adults 25+)
Cities & Places in San Mateo County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| San Mateo | 103,105 | $153,504 | 8.2% | $1,618,700 |
| Daly City | 101,964 | $123,547 | 7.7% | $1,115,000 |
| Redwood City | 82,447 | $157,814 | 6.3% | $1,801,700 |
| South San Francisco | 64,305 | $136,578 | 6.7% | $1,188,800 |
| San Bruno | 42,307 | $141,272 | 6.0% | $1,207,500 |
| Pacifica | 37,261 | $160,523 | 5.8% | $1,249,800 |
| Foster City | 32,792 | $199,143 | 4.1% | $1,838,200 |
| Menlo Park | 32,727 | $210,025 | 5.8% | $2,000,000+ |
| Burlingame | 30,525 | $174,000 | 7.1% | $2,000,000+ |
| San Carlos | 29,614 | $237,470 | 3.3% | $2,000,000+ |
| East Palo Alto | 29,069 | $113,493 | 10.3% | $1,102,600 |
| Belmont | 27,337 | $205,297 | 6.9% | $2,000,000+ |
| Millbrae | 22,689 | $163,476 | 6.0% | $1,934,900 |
| North Fair Oaks | 13,100 | $104,884 | 13.0% | $1,276,900 |
| Half Moon Bay | 11,391 | $157,884 | 5.6% | $1,549,500 |
| Hillsborough | 11,099 | $250,000+ | 5.0% | $2,000,000+ |
| Atherton | 6,993 | $250,000+ | 5.3% | $2,000,000+ |
| El Granada | 5,232 | $213,347 | 5.4% | $1,424,700 |
| Woodside | 5,126 | $250,000+ | 4.5% | $2,000,000+ |
| Brisbane | 4,692 | $156,169 | 5.5% | $1,232,200 |
| Broadmoor | 4,586 | $167,396 | 2.5% | $1,254,600 |
| Portola Valley | 4,305 | $250,000+ | 6.2% | $2,000,000+ |
| Emerald Lake Hills | 4,235 | $250,000+ | 4.6% | $2,000,000+ |
| West Menlo Park | 3,634 | $250,000+ | 3.0% | $2,000,000+ |
| Montara | 2,917 | $233,826 | 3.4% | $1,580,700 |
| Moss Beach | 2,683 | $99,680 | 9.1% | $1,123,100 |
| Highlands | 2,450 | $250,000+ | 3.9% | $2,000,000+ |
| Colma | 1,636 | $148,295 | 6.7% | $1,062,000 |
| Baywood Park | 1,580 | $217,206 | 2.8% | $2,000,000+ |
| Ladera | 1,297 | $235,750 | 1.5% | $2,000,000+ |
| La Honda | 1,269 | $250,000+ | 5.0% | $935,500 |
| Pescadero | 691 | $250,000+ | 9.1% | $1,958,300 |
| Loma Mar | 309 | $250,000+ | 0.0% | $1,073,100 |
Explore California Rankings
Population Overview
San Mateo County is located in California with a total population of 742,340. It is the 15th most populous county out of 58 in California. The county encompasses 33 Census-designated places.
Age Demographics
The median age in San Mateo County is 40.9 years. This is 8% higher than the state median of 37.9 years.
Economy, Income & Housing
The median household income in San Mateo County is $158,855. This is 60% higher than the state median of $99,122. It is also 97% higher than the national median of $80,734. The poverty rate stands at 6.7%. This is 44% lower than the state poverty rate of 12.0%. The unemployment rate is 4.8%. This is 28% lower than the state rate of 6.6%. The median home value is $1,559,600. Housing costs are 112% higher than the state median of $734,700. The home-value-to-income ratio of 9.8x suggests that housing affordability is a significant concern for many residents. 58.5% of occupied housing units are owner-occupied. This homeownership rate is 5% higher than the state average of 55.9%.
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 31.0%. The Black or African American population (2.0%) is well below the state average of 5.2%. The Asian population is significantly higher than the state average (31.0% vs 15.3%).
Education
53.7% of residents aged 25 and older hold a bachelor's degree or higher. This places San Mateo County in the top 10% of all counties in the state for educational attainment. This is 45% 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 90.3%. Notably, 24.1% of adults hold a graduate or professional degree, indicating a highly educated workforce.
Data Sources & Methodology
All figures for San Mateo 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.
Frequently Asked Questions
What is the population of San Mateo County, California?
San Mateo County has a population of 742,340, making it the 15th most populous county in California.
What is the median income in San Mateo County?
The median household income in San Mateo County is $158,855 with a poverty rate of 6.7%.
How many cities are in San Mateo County, California?
San Mateo County contains 33 Census-designated places.