Data / Rankings / Population aged 18 to 64 / Counties in Washington

Counties in Washington by population aged 18 to 64, 2025

Whitman County had the highest population aged 18 to 64 of 39 counties in 2025, at 70.9%. Jefferson County had the lowest, at 45.1%. The median was 55.5% and the figure for Washington was 61.3%. Source: the U.S. Census Bureau.

Highest70.9Whitman County
Lowest45.1Jefferson County
Median55.539 counties
Washington61.3History

All counties, 2025

Whitman County: 70.9 %Whitman County70.9King County: 66.2 %King County66.2Kittitas County: 62.3 %Kittitas County62.3Snohomish County: 62.1 %Snohomish County62.1Whatcom County: 61.4 %Whatcom County61.4Pierce County: 61.3 %Pierce County61.3Clark County: 60.4 %Clark County60.4Spokane County: 59.9 %Spokane County59.9Franklin County: 59.9 %Franklin County59.9Thurston County: 59.4 %Thurston County59.4Kitsap County: 59.4 %Kitsap County59.4Walla Walla County: 58.3 %Walla Walla County58.3Benton County: 58 %Benton County58Douglas County: 57.7 %Douglas County57.7Grant County: 57.4 %Grant County57.4Yakima County: 57.3 %Yakima County57.3Skamania County: 56.9 %Skamania County56.9Cowlitz County: 56.7 %Cowlitz County56.7Chelan County: 55.6 %Chelan County55.6Grays Harbor County: 55.5 %Grays Harbor County55.5Lewis County: 55.4 %Lewis County55.4Klickitat County: 55.4 %Klickitat County55.4Mason County: 55.3 %Mason County55.3Adams County: 55.1 %Adams County55.1Skagit County: 54.9 %Skagit County54.9Okanogan County: 54.5 %Okanogan County54.5Island County: 53.2 %Island County53.2Asotin County: 53 %Asotin County53Stevens County: 51.7 %Stevens County51.7Columbia County: 51.6 %Columbia County51.6Pend Oreille County: 51 %Pend Oreille County51Ferry County: 50.9 %Ferry County50.9Lincoln County: 50.6 %Lincoln County50.6Pacific County: 50.5 %Pacific County50.5Garfield County: 50.1 %Garfield County50.1Wahkiakum County: 49.9 %Wahkiakum County49.9Clallam County: 49.5 %Clallam County49.5San Juan County: 48.8 %San Juan County48.8Jefferson County: 45.1 %Jefferson County45.1
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2025 (%)Change on 2024
1Whitman County70.9+0.1 pts
2King County66.20 pts
3Kittitas County62.3-0.3 pts
4Snohomish County62.1-0.1 pts
5Whatcom County61.4-0.1 pts
6Pierce County61.3-0.1 pts
7Clark County60.40 pts
8Spokane County59.9-0.1 pts
9Franklin County59.9+0.4 pts
10Thurston County59.4-0 pts
11Kitsap County59.4-0.1 pts
12Walla Walla County58.3+0.1 pts
13Benton County58+0.1 pts
14Douglas County57.7+0.2 pts
15Grant County57.4+0.2 pts
16Yakima County57.3+0.2 pts
17Skamania County56.9-0.9 pts
18Cowlitz County56.7-0.1 pts
19Chelan County55.6-0.2 pts
20Grays Harbor County55.5-0.4 pts
21Lewis County55.4-0 pts
22Klickitat County55.4-0.5 pts
23Mason County55.3-0.1 pts
24Adams County55.1+0.1 pts
25Skagit County54.9-0 pts
26Okanogan County54.5+0.3 pts
27Island County53.2-0.6 pts
28Asotin County53-0.6 pts
29Stevens County51.7-0.3 pts
30Columbia County51.6-0.7 pts
31Pend Oreille County51-0.4 pts
32Ferry County50.9+0.1 pts
33Lincoln County50.6-0.3 pts
34Pacific County50.5-0.3 pts
35Garfield County50.1-0.7 pts
36Wahkiakum County49.9-0.4 pts
37Clallam County49.5-0.4 pts
38San Juan County48.8-0.4 pts
39Jefferson County45.1-0.4 pts

Other periods

About this ranking

Residents aged 18 to 64 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.

Not comparable with working-age shares for ages 15 to 64 used in EU and World Bank statistics.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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 styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 18 to 64 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 (Counties in Washington by population aged 18 to 64, 2025) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: residents aged 18 to 64 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, Counties in Washington by population aged 18 to 64, 2025. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-18-64/washington-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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. Counties in Washington by population aged 18 to 64, 2025. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-18-64/washington-counties.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 18 to 64 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, Counties in Washington by population aged 18 to 64, 2025 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/washington-counties (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_washington_by_2025,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 18 to 64 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: Counties in Washington by population aged 18 to 64, 2025}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/population-18-64/washington-counties. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: residents aged 18 to 64 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: Counties in Washington by population aged 18 to 64, 2025
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/population-18-64/washington-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/washington-counties.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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.
ER  -
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Questions

Which county has the highest population aged 18 to 64?

Whitman County, with 70.9% in 2025, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Jefferson County, with 45.1% in 2025.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program, county population by age and sex: residents aged 18 to 64 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. Retrieved 2026-10-12.

Population aged 18 to 64: other rankings

Counties in Washington: more rankings