# Counties in Washington by population under 18, 2025

All 39 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/washington-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Adams County | 32.7 |
| 2 | Franklin County | 28.9 |
| 3 | Yakima County | 26.7 |
| 4 | Grant County | 26.7 |
| 5 | Benton County | 24.7 |
| 6 | Douglas County | 22.3 |
| 7 | Pierce County | 22 |
| 8 | Cowlitz County | 21.9 |
| 9 | Lewis County | 21.8 |
| 10 | Garfield County | 21.6 |
| 11 | Chelan County | 21.6 |
| 12 | Snohomish County | 21.5 |
| 13 | Clark County | 21.1 |
| 14 | Lincoln County | 20.9 |
| 15 | Spokane County | 20.7 |
| 16 | Stevens County | 20.5 |
| 17 | Okanogan County | 20.3 |
| 18 | Skagit County | 20.2 |
| 19 | Thurston County | 20 |
| 20 | Pend Oreille County | 19.8 |
| 21 | Asotin County | 19.7 |
| 22 | Walla Walla County | 19.6 |
| 23 | Ferry County | 19.1 |
| 24 | Grays Harbor County | 19 |
| 25 | Mason County | 18.9 |
| 26 | Kitsap County | 18.7 |
| 27 | King County | 18.6 |
| 28 | Klickitat County | 18.2 |
| 29 | Whatcom County | 17.7 |
| 30 | Columbia County | 17.3 |
| 31 | Kittitas County | 17.2 |
| 32 | Skamania County | 17.1 |
| 33 | Island County | 16.4 |
| 34 | Wahkiakum County | 15.9 |
| 35 | Whitman County | 15.7 |
| 36 | Clallam County | 15.3 |
| 37 | Pacific County | 14.9 |
| 38 | San Juan County | 12.5 |
| 39 | Jefferson County | 10.7 |