Data / Rankings / Population density / Counties in Washington

Counties in Washington by population density, 2025

King County had the highest population density of 39 counties in 2025, at 427.9 inhabitants per km². Garfield County had the lowest, at 1.3 inhabitants per km². The median was 15.2 inhabitants per km² and the figure for Washington was 46.5 inhabitants per km². Source: the U.S. Census Bureau.

Highest427.9King County
Lowest1.3Garfield County
Median15.239 counties
Washington46.5History

All counties, 2025

CSVChart (SVG)

King CountyKing County: 427.9 inhabitants per km²427.9Clark CountyClark County: 326.9 inhabitants per km²326.9Kitsap CountyKitsap County: 276.9 inhabitants per km²276.9Pierce CountyPierce County: 219 inhabitants per km²219Thurston CountyThurston County: 162.6 inhabitants per km²162.6Snohomish CountySnohomish County: 161.1 inhabitants per km²161.1Island CountyIsland County: 158.5 inhabitants per km²158.5Spokane CountySpokane County: 122.2 inhabitants per km²122.2Benton CountyBenton County: 50.4 inhabitants per km²50.4Whatcom CountyWhatcom County: 43.3 inhabitants per km²43.3San Juan CountySan Juan County: 41.2 inhabitants per km²41.2Cowlitz CountyCowlitz County: 38.9 inhabitants per km²38.9Franklin CountyFranklin County: 31.9 inhabitants per km²31.9Skagit CountySkagit County: 29.7 inhabitants per km²29.7Mason CountyMason County: 28.6 inhabitants per km²28.6Yakima CountyYakima County: 23.3 inhabitants per km²23.3Walla Walla CountyWalla Walla County: 19 inhabitants per km²19Clallam CountyClallam County: 17.4 inhabitants per km²17.4Grays Harbor CountyGrays Harbor County: 15.9 inhabitants per km²15.9Grant CountyGrant County: 15.2 inhabitants per km²15.2Lewis CountyLewis County: 14.2 inhabitants per km²14.2Asotin CountyAsotin County: 13.7 inhabitants per km²13.7Chelan CountyChelan County: 10.8 inhabitants per km²10.8Pacific CountyPacific County: 10.1 inhabitants per km²10.1Douglas CountyDouglas County: 9.9 inhabitants per km²9.9Whitman CountyWhitman County: 8.7 inhabitants per km²8.7Kittitas CountyKittitas County: 8.2 inhabitants per km²8.2Stevens CountyStevens County: 7.7 inhabitants per km²7.7Jefferson CountyJefferson County: 7.3 inhabitants per km²7.3Wahkiakum CountyWahkiakum County: 7.2 inhabitants per km²7.2Klickitat CountyKlickitat County: 5 inhabitants per km²5Adams CountyAdams County: 4.3 inhabitants per km²4.3Pend Oreille CountyPend Oreille County: 4 inhabitants per km²4Okanogan CountyOkanogan County: 3.3 inhabitants per km²3.3Skamania CountySkamania County: 3 inhabitants per km²3Lincoln CountyLincoln County: 2 inhabitants per km²2Columbia CountyColumbia County: 1.8 inhabitants per km²1.8Ferry CountyFerry County: 1.3 inhabitants per km²1.3Garfield CountyGarfield County: 1.3 inhabitants per km²1.3
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2025
inhabitants per km²		Change on 2024
1King County427.9+1.2%
2Clark County326.9+1.1%
3Kitsap County276.9+0.9%
4Pierce County219+0.7%
5Thurston County162.6+0.7%
6Snohomish County161.1+1.1%
7Island County158.5-0.4%
8Spokane County122.2+0.5%
9Benton County50.4+1.3%
10Whatcom County43.3+0.8%
11San Juan County41.2+0.1%
12Cowlitz County38.9+1%
13Franklin County31.9+1.2%
14Skagit County29.7+0.5%
15Mason County28.6+2%
16Yakima County23.3+0.1%
17Walla Walla County19+0.4%
18Clallam County17.4+0.3%
19Grays Harbor County15.9+0.2%
20Grant County15.2+0.8%
21Lewis County14.2+1.1%
22Asotin County13.70%
23Chelan County10.8+0.7%
24Pacific County10.1+0.5%
25Douglas County9.9+2.1%
26Whitman County8.7+1.4%
27Kittitas County8.2+1.4%
28Stevens County7.7+1%
29Jefferson County7.3+0.2%
30Wahkiakum County7.2+1.2%
31Klickitat County5+1.4%
32Adams County4.3+0.8%
33Pend Oreille County4+0.6%
34Okanogan County3.3+1.3%
35Skamania County3+0.2%
36Lincoln County2+1.3%
37Columbia County1.8+2.3%
38Ferry County1.3-0.5%
39Garfield County1.3+0.6%

Other periods

About this ranking

Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.

United States: Census Bureau population estimates for 1 July divided by land area (water excluded) from the latest Census Gazetteer files. US tables often give people per square mile; multiply persons per km² by 2.59 to compare.

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 resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-09.

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Questions

Which county has the highest population density?

King County, with 427.9 inhabitants per km² in 2025, according to the U.S. Census Bureau.

Which county has the lowest population density?

Garfield County, with 1.3 inhabitants per km² 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 resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². Retrieved 2026-10-09.

Population density: other rankings

Counties in Washington: more rankings