Median Age in Marin County, CA
ACS 2024 5-Year Estimates
47.4 years
Rank #410/3,222 · #10 in CA
87th
Marin 47.4 years
CA 37.9 years +25.1%
US 38.9 years +21.9%
Median Age Trend
Rankings →Percentile Rank Over Time
Year-over-Year Age Change
National Distribution
How Marin County's median age of 47.4 years compares to all 3,222 U.S. counties. Values range from 21.4 years to 86.2 years.
Distribution of Median Age Across All Counties
Ranking Context
Counties ranked closest to Marin County for median age.
Nearby Rankings
Full ranking →| #407 | Clay County, TX | 47.5 years |
| #408 | Oconto County, WI | 47.5 years |
| #409 | Choctaw County, AL | 47.4 years |
| #410 | Marin County, CA | 47.4 years |
| #411 | Putnam County, IL | 47.4 years |
| #412 | Waldo County, ME | 47.4 years |
| #413 | Lac qui Parle County, MN | 47.4 years |
About Median Age
Marin County, California has a median age of 47.4 years, ranking #410 of 3,222 counties nationwide — 21.9% above the national value of 38.9 years. Within California, it ranks #10 of 58. This places it in the 87th percentile nationally.
The median age of the total population. Source: U.S. Census Bureau, American Community Survey 2024 5-Year Estimates. All values are estimates derived from survey samples and are subject to margin of error. For more information, see our methodology.