# Counties in California by population under 18, 2025

All 58 values come from U.S. Census Bureau for 2025, so the places are comparable.

- Indicator id: `population_0_17_share`
- Unit: %
- Definition: Residents aged 0 to 17 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.
- Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (https://www.census.gov/programs-surveys/popest/data/data-sets.html)
- Retrieved: 2026-10-12
- Citation: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/population-under-18/california-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Tulare County | 28.1 |
| 2 | Kern County | 27.1 |
| 3 | Merced County | 26.8 |
| 4 | Fresno County | 26.3 |
| 5 | Yuba County | 26.2 |
| 6 | Madera County | 26.2 |
| 7 | Imperial County | 26.2 |
| 8 | Colusa County | 25.9 |
| 9 | Kings County | 25.4 |
| 10 | Stanislaus County | 25.2 |
| 11 | San Joaquin County | 24.7 |
| 12 | Glenn County | 24.6 |
| 13 | San Bernardino County | 24.1 |
| 14 | San Benito County | 24 |
| 15 | Sutter County | 23.8 |
| 16 | Monterey County | 23.7 |
| 17 | Tehama County | 23.7 |
| 18 | Riverside County | 23 |
| 19 | Sacramento County | 22 |
| 20 | Santa Barbara County | 21.6 |
| 21 | Placer County | 21.3 |
| 22 | Contra Costa County | 21.1 |
| 23 | Lake County | 20.9 |
| 24 | Shasta County | 20.9 |
| 25 | Solano County | 20.8 |
| 26 | Ventura County | 20.5 |
| 27 | Butte County | 20.1 |
| 28 | Del Norte County | 20.1 |
| 29 | San Diego County | 19.9 |
| 30 | Orange County | 19.5 |
| 31 | Mendocino County | 19.5 |
| 32 | Modoc County | 19.4 |
| 33 | Los Angeles County | 19.2 |
| 34 | Alameda County | 19 |
| 35 | El Dorado County | 19 |
| 36 | Inyo County | 18.9 |
| 37 | Lassen County | 18.8 |
| 38 | Santa Clara County | 18.8 |
| 39 | Siskiyou County | 18.8 |
| 40 | Yolo County | 18.6 |
| 41 | San Mateo County | 18.5 |
| 42 | Mono County | 18.5 |
| 43 | Marin County | 18.3 |
| 44 | Napa County | 18.1 |
| 45 | Sonoma County | 18.1 |
| 46 | Mariposa County | 17.9 |
| 47 | Humboldt County | 17.9 |
| 48 | Calaveras County | 17.7 |
| 49 | San Luis Obispo County | 17 |
| 50 | Santa Cruz County | 17 |
| 51 | Nevada County | 16.8 |
| 52 | Tuolumne County | 16.8 |
| 53 | Plumas County | 16.2 |
| 54 | Amador County | 15.9 |
| 55 | Sierra County | 15.3 |
| 56 | Trinity County | 15.2 |
| 57 | San Francisco County | 13.1 |
| 58 | Alpine County | 12.9 |