# Counties in California by median age, 2024

All 58 values come from U.S. Census Bureau for 2024, so the places are comparable.

- Indicator id: `median_age`
- Unit: years
- Definition: Age that divides the resident population into two halves of equal size. Spain and the EU: on 1 January. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.
- Source: U.S. Census Bureau, American Community Survey 5-year estimates, table B01002: median age, total population (https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b01002.dat)
- Retrieved: 2026-10-08
- Citation: U.S. Census Bureau. American Community Survey 5-year estimates, table B01002: median age, total population. https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b01002.dat. Retrieved 2026-10-08.
- Web page: https://invokely.ai/rankings/median-age/california-counties
- CSV: https://invokely.ai/download/rankings/median-age/california-counties.csv

| Rank | Place | years |
|---:|---|---:|
| 1 | Trinity County | 54.9 |
| 2 | Sierra County | 54.7 |
| 3 | Calaveras County | 52 |
| 3 | Plumas County | 52 |
| 5 | Mariposa County | 51.2 |
| 6 | Nevada County | 50.1 |
| 7 | Amador County | 49.7 |
| 8 | Tuolumne County | 48.4 |
| 9 | Modoc County | 47.5 |
| 10 | Marin County | 47.4 |
| 11 | Siskiyou County | 47.2 |
| 12 | El Dorado County | 46.1 |
| 13 | Inyo County | 45.5 |
| 14 | Lake County | 44.1 |
| 14 | Mendocino County | 44.1 |
| 16 | Napa County | 42.9 |
| 16 | Sonoma County | 42.9 |
| 18 | Placer County | 42.5 |
| 19 | Shasta County | 41.7 |
| 20 | Mono County | 41.5 |
| 21 | San Mateo County | 40.9 |
| 22 | Contra Costa County | 40.5 |
| 23 | San Luis Obispo County | 40.4 |
| 24 | San Francisco County | 40 |
| 24 | Tehama County | 40 |
| 26 | Del Norte County | 39.9 |
| 26 | Humboldt County | 39.9 |
| 28 | Alpine County | 39.8 |
| 28 | Santa Cruz County | 39.8 |
| 30 | Ventura County | 39.6 |
| 31 | Orange County | 39.4 |
| 32 | Solano County | 39.2 |
| 33 | Alameda County | 39 |
| 34 | Lassen County | 38.3 |
| 35 | Los Angeles County | 38.2 |
| 36 | Santa Clara County | 38.1 |
| 37 | Sacramento County | 37.5 |
| 38 | San Diego County | 37.3 |
| 39 | Riverside County | 37 |
| 40 | Sutter County | 36.5 |
| 41 | Butte County | 36.2 |
| 41 | Glenn County | 36.2 |
| 43 | San Benito County | 36.1 |
| 44 | Colusa County | 35.9 |
| 45 | Monterey County | 35.5 |
| 46 | San Joaquin County | 35.4 |
| 47 | Stanislaus County | 34.9 |
| 48 | San Bernardino County | 34.7 |
| 49 | Madera County | 34.6 |
| 49 | Santa Barbara County | 34.6 |
| 51 | Yuba County | 34.2 |
| 52 | Fresno County | 33.5 |
| 53 | Imperial County | 33.2 |
| 54 | Kern County | 32.7 |
| 55 | Kings County | 32.5 |
| 56 | Tulare County | 32.1 |
| 56 | Yolo County | 32.1 |
| 58 | Merced County | 31.8 |