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

Counties in Washington by population aged 18 to 64

Whitman County had the highest population aged 18 to 64 of 39 counties in 2018, at 73.1%. Jefferson County had the lowest, at 50.5%. The median was 57.4% and the figure for Washington was 62.4%. Source: the U.S. Census Bureau.

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Highest73.1Whitman County
Lowest50.5Jefferson County
Median57.439 counties
Washington62.4History

Map of counties, 2018

Adams County: 54.7 %Asotin County: 56.5 %Benton County: 58.4 %Chelan County: 57.7 %Clallam County: 52.9 %Clark County: 60.5 %Columbia County: 53.8 %Cowlitz County: 57.9 %Douglas County: 57.4 %Ferry County: 52.8 %Franklin County: 58.7 %Garfield County: 52.3 %Grant County: 57.1 %Grays Harbor County: 58.5 %Island County: 56.8 %Jefferson County: 50.5 %King County: 66.5 %Kitsap County: 61.4 %Kittitas County: 63.9 %Klickitat County: 57.4 %Lewis County: 57.1 %Lincoln County: 52.9 %Mason County: 58.2 %Okanogan County: 55 %Pacific County: 52.5 %Pend Oreille County: 54.7 %Pierce County: 62.8 %San Juan County: 52.9 %Skagit County: 56.9 %Skamania County: 61.6 %Snohomish County: 63.5 %Spokane County: 61.3 %Stevens County: 55.1 %Thurston County: 60.9 %Wahkiakum County: 52.4 %Walla Walla County: 60.4 %Whatcom County: 62.5 %Whitman County: 73.1 %Yakima County: 57.3 %
  • Under 53
  • 53 to 56
  • 56 to 57
  • 57 to 59
  • 59 to 62
  • 62 and over
%, 2018. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2018

Whitman County: 73.1 %Whitman County73.1King County: 66.5 %King County66.5Kittitas County: 63.9 %Kittitas County63.9Snohomish County: 63.5 %Snohomish County63.5Pierce County: 62.8 %Pierce County62.8Whatcom County: 62.5 %Whatcom County62.5Skamania County: 61.6 %Skamania County61.6Kitsap County: 61.4 %Kitsap County61.4Spokane County: 61.3 %Spokane County61.3Thurston County: 60.9 %Thurston County60.9Clark County: 60.5 %Clark County60.5Walla Walla County: 60.4 %Walla Walla County60.4Franklin County: 58.7 %Franklin County58.7Grays Harbor County: 58.5 %Grays Harbor County58.5Benton County: 58.4 %Benton County58.4Mason County: 58.2 %Mason County58.2Cowlitz County: 57.9 %Cowlitz County57.9Chelan County: 57.7 %Chelan County57.7Douglas County: 57.4 %Douglas County57.4Klickitat County: 57.4 %Klickitat County57.4Yakima County: 57.3 %Yakima County57.3Grant County: 57.1 %Grant County57.1Lewis County: 57.1 %Lewis County57.1Skagit County: 56.9 %Skagit County56.9Island County: 56.8 %Island County56.8Asotin County: 56.5 %Asotin County56.5Stevens County: 55.1 %Stevens County55.1Okanogan County: 55 %Okanogan County55Adams County: 54.7 %Adams County54.7Pend Oreille County: 54.7 %Pend Oreille County54.7Columbia County: 53.8 %Columbia County53.8Lincoln County: 52.9 %Lincoln County52.9San Juan County: 52.9 %San Juan County52.9Clallam County: 52.9 %Clallam County52.9Ferry County: 52.8 %Ferry County52.8Pacific County: 52.5 %Pacific County52.5Wahkiakum County: 52.4 %Wahkiakum County52.4Garfield County: 52.3 %Garfield County52.3Jefferson County: 50.5 %Jefferson County50.5Whitman County: 73.1 %Whitman County73.1King County: 66.5 %King County66.5Kittitas County: 63.9 %Kittitas County63.9Snohomish County: 63.5 %Snohomish County63.5Pierce County: 62.8 %Pierce County62.8Whatcom County: 62.5 %Whatcom County62.5Skamania County: 61.6 %Skamania County61.6Kitsap County: 61.4 %Kitsap County61.4Spokane County: 61.3 %Spokane County61.3Thurston County: 60.9 %Thurston County60.9Clark County: 60.5 %Clark County60.5Walla Walla County: 60.4 %Walla Walla County60.4Franklin County: 58.7 %Franklin County58.7Grays Harbor County: 58.5 %Grays Harbor County58.5Benton County: 58.4 %Benton County58.4Mason County: 58.2 %Mason County58.2Cowlitz County: 57.9 %Cowlitz County57.9Chelan County: 57.7 %Chelan County57.7Douglas County: 57.4 %Douglas County57.4Klickitat County: 57.4 %Klickitat County57.4Yakima County: 57.3 %Yakima County57.3Grant County: 57.1 %Grant County57.1Lewis County: 57.1 %Lewis County57.1Skagit County: 56.9 %Skagit County56.9Island County: 56.8 %Island County56.8Asotin County: 56.5 %Asotin County56.5Stevens County: 55.1 %Stevens County55.1Okanogan County: 55 %Okanogan County55Adams County: 54.7 %Adams County54.7Pend Oreille County: 54.7 %Pend Oreille County54.7Columbia County: 53.8 %Columbia County53.8Lincoln County: 52.9 %Lincoln County52.9San Juan County: 52.9 %San Juan County52.9Clallam County: 52.9 %Clallam County52.9Ferry County: 52.8 %Ferry County52.8Pacific County: 52.5 %Pacific County52.5Wahkiakum County: 52.4 %Wahkiakum County52.4Garfield County: 52.3 %Garfield County52.3Jefferson County: 50.5 %Jefferson County50.5
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2018 (%)Change on 2017
1Whitman County73.1-0.3 pts
2King County66.5-0.1 pts
3Kittitas County63.9-0.6 pts
4Snohomish County63.5-0.3 pts
5Pierce County62.8-0.2 pts
6Whatcom County62.5-0.4 pts
7Skamania County61.6-0.4 pts
8Kitsap County61.4-0.4 pts
9Spokane County61.3-0.3 pts
10Thurston County60.9-0.3 pts
11Clark County60.5-0.1 pts
12Walla Walla County60.4-0.4 pts
13Franklin County58.7+0.1 pts
14Grays Harbor County58.5-0.5 pts
15Benton County58.4-0.3 pts
16Mason County58.2-0.1 pts
17Cowlitz County57.9-0.3 pts
18Chelan County57.7-0.2 pts
19Douglas County57.4+0.1 pts
20Klickitat County57.4-0.4 pts
21Yakima County57.3-0.1 pts
22Grant County57.1+0.1 pts
23Lewis County57.1-0.1 pts
24Skagit County56.9-0.4 pts
25Island County56.8-0.7 pts
26Asotin County56.5-0.5 pts
27Stevens County55.1-0.6 pts
28Okanogan County55-0.5 pts
29Adams County54.7-0.1 pts
30Pend Oreille County54.7-0.7 pts
31Columbia County53.8-0.2 pts
32Lincoln County52.90 pts
33San Juan County52.9-0.8 pts
34Clallam County52.9-0.6 pts
35Ferry County52.8-1.3 pts
36Pacific County52.5-0.5 pts
37Wahkiakum County52.4+0.4 pts
38Garfield County52.3-0.9 pts
39Jefferson County50.5-1 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, 2018) [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, 2018. 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?period=2018. 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, 2018. 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?period=2018.

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, 2018 [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?period=2018 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_washington_by_2018,
  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, 2018}},
  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?period=2018. 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, 2018
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?period=2018
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/washington-counties?period=2018.
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 73.1% in 2018, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Jefferson County, with 50.5% in 2018.

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