Data / Rankings / Population density / Counties in Washington

Counties in Washington by population density

King County had the highest population density of 39 counties in 2021, at 411.2 inhabitants per km². Garfield County had the lowest, at 1.3 inhabitants per km². The median was 14.5 inhabitants per km² and the figure for Washington was 45 inhabitants per km². Source: the U.S. Census Bureau.

Highest411.2King County
Lowest1.3Garfield County
Median14.539 counties
Washington45History

All counties, 2021

CSVChart (SVG)

King CountyKing County: 411.2 inhabitants per km²411.2Clark CountyClark County: 314.9 inhabitants per km²314.9Kitsap CountyKitsap County: 270.4 inhabitants per km²270.4Pierce CountyPierce County: 214.8 inhabitants per km²214.8Island CountyIsland County: 162.1 inhabitants per km²162.1Thurston CountyThurston County: 159.4 inhabitants per km²159.4Snohomish CountySnohomish County: 154.7 inhabitants per km²154.7Spokane CountySpokane County: 119.4 inhabitants per km²119.4Benton CountyBenton County: 47.8 inhabitants per km²47.8Whatcom CountyWhatcom County: 41.5 inhabitants per km²41.5San Juan CountySan Juan County: 41.4 inhabitants per km²41.4Cowlitz CountyCowlitz County: 37.8 inhabitants per km²37.8Franklin CountyFranklin County: 30.5 inhabitants per km²30.5Skagit CountySkagit County: 29.2 inhabitants per km²29.2Mason CountyMason County: 27.1 inhabitants per km²27.1Yakima CountyYakima County: 23.1 inhabitants per km²23.1Walla Walla CountyWalla Walla County: 18.9 inhabitants per km²18.9Clallam CountyClallam County: 17.4 inhabitants per km²17.4Grays Harbor CountyGrays Harbor County: 15.6 inhabitants per km²15.6Grant CountyGrant County: 14.5 inhabitants per km²14.5Asotin CountyAsotin County: 13.6 inhabitants per km²13.6Lewis CountyLewis County: 13.6 inhabitants per km²13.6Chelan CountyChelan County: 10.6 inhabitants per km²10.6Pacific CountyPacific County: 9.9 inhabitants per km²9.9Douglas CountyDouglas County: 9.3 inhabitants per km²9.3Whitman CountyWhitman County: 7.7 inhabitants per km²7.7Kittitas CountyKittitas County: 7.7 inhabitants per km²7.7Stevens CountyStevens County: 7.4 inhabitants per km²7.4Jefferson CountyJefferson County: 7.2 inhabitants per km²7.2Wahkiakum CountyWahkiakum County: 6.7 inhabitants per km²6.7Klickitat CountyKlickitat County: 4.8 inhabitants per km²4.8Adams CountyAdams County: 4.1 inhabitants per km²4.1Pend Oreille CountyPend Oreille County: 3.8 inhabitants per km²3.8Okanogan CountyOkanogan County: 3.1 inhabitants per km²3.1Skamania CountySkamania County: 2.8 inhabitants per km²2.8Lincoln CountyLincoln County: 1.9 inhabitants per km²1.9Columbia 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

RankCounties2021
inhabitants per km²		Change on 2020
1King County411.2-0.9%
2Clark County314.9+1.5%
3Kitsap County270.4+0.3%
4Pierce County214.8+0.5%
5Island County162.1+0.7%
6Thurston County159.4+0.8%
7Snohomish County154.7+0.8%
8Spokane County119.4+0.8%
9Benton County47.8+1.5%
10Whatcom County41.5-0.3%
11San Juan County41.4+4.5%
12Cowlitz County37.8+0.6%
13Franklin County30.5+1%
14Skagit County29.2+0.9%
15Mason County27.1+1.9%
16Yakima County23.10%
17Walla Walla County18.9-0.6%
18Clallam County17.4+1.4%
19Grays Harbor County15.6+1.4%
20Grant County14.5+1%
21Asotin County13.6+0.6%
22Lewis County13.6+2.5%
23Chelan County10.6+0.7%
24Pacific County9.9+2.2%
25Douglas County9.3+1.9%
26Whitman County7.7-9.5%
27Kittitas County7.7-2.5%
28Stevens County7.4+2.2%
29Jefferson County7.2+1.5%
30Wahkiakum County6.7+3.2%
31Klickitat County4.8+1.6%
32Adams County4.1+0.2%
33Pend Oreille County3.8+2.9%
34Okanogan County3.1+1.5%
35Skamania County2.8+1.5%
36Lincoln County1.9+3.2%
37Columbia County1.8+1.6%
38Ferry County1.3+1.3%
39Garfield County1.3+2.2%

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 411.2 inhabitants per km² in 2021, according to the U.S. Census Bureau.

Which county has the lowest population density?

Garfield County, with 1.3 inhabitants per km² in 2021.

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