Median Age in San Mateo County, CA
ACS 2024 5-Year Estimates
How San Mateo County Compares
National Distribution
Where San Mateo County falls among all 3,222 U.S. counties for median age.
■ San Mateo County: 40.9 years
Ranking Context
| Rank | County | Value |
|---|---|---|
| #1,817 | Jefferson County, WV | 41.0 years |
| #1,818 | Cross County, AR | 40.9 years |
| #1,819 | Phillips County, AR | 40.9 years |
| #1,820 | San Mateo County, CA | 40.9 years |
| #1,821 | Lincoln County, CO | 40.9 years |
| #1,822 | Phillips County, CO | 40.9 years |
| #1,823 | Jefferson County, GA | 40.9 years |
Median Age in San Mateo County, California
San Mateo County, California has a median age of 40.9 years, which ranks #1,820 of 3,222 out of 3,222 counties nationwide. This is 5.1% above the national value of 38.9 years.
Within California, San Mateo County ranks #21 of 58 out of 58 counties. This places it in the 44th percentile nationally.
The median age of the total population. All data comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates for 2024.
About this data
Source: U.S. Census Bureau, American Community Survey 5-Year Estimates (2024). All values are estimates derived from survey samples and are subject to margin of error. For more information, see our methodology.