Data / Rankings / Population density / Counties in Washington

Counties in Washington by population density

King County had the highest population density of 39 counties in 2020, at 415 inhabitants per km². Garfield County had the lowest, at 1.2 inhabitants per km². The median was 14.3 inhabitants per km² and the figure for Washington was 44.9 inhabitants per km². Source: the U.S. Census Bureau.

Highest415King County
Lowest1.2Garfield County
Median14.339 counties
Washington44.9History

All counties, 2020

CSVChart (SVG)

King CountyKing County: 415 inhabitants per km²415Clark CountyClark County: 310.4 inhabitants per km²310.4Kitsap CountyKitsap County: 269.5 inhabitants per km²269.5Pierce CountyPierce County: 213.8 inhabitants per km²213.8Island CountyIsland County: 161 inhabitants per km²161Thurston CountyThurston County: 158.2 inhabitants per km²158.2Snohomish CountySnohomish County: 153.6 inhabitants per km²153.6Spokane CountySpokane County: 118.4 inhabitants per km²118.4Benton CountyBenton County: 47.1 inhabitants per km²47.1Whatcom CountyWhatcom County: 41.7 inhabitants per km²41.7San Juan CountySan Juan County: 39.6 inhabitants per km²39.6Cowlitz CountyCowlitz County: 37.6 inhabitants per km²37.6Franklin CountyFranklin County: 30.2 inhabitants per km²30.2Skagit CountySkagit County: 29 inhabitants per km²29Mason CountyMason County: 26.6 inhabitants per km²26.6Yakima CountyYakima County: 23.1 inhabitants per km²23.1Walla Walla CountyWalla Walla County: 19 inhabitants per km²19Clallam CountyClallam County: 17.2 inhabitants per km²17.2Grays Harbor CountyGrays Harbor County: 15.4 inhabitants per km²15.4Grant CountyGrant County: 14.3 inhabitants per km²14.3Asotin CountyAsotin County: 13.6 inhabitants per km²13.6Lewis CountyLewis County: 13.3 inhabitants per km²13.3Chelan CountyChelan County: 10.5 inhabitants per km²10.5Pacific CountyPacific County: 9.7 inhabitants per km²9.7Douglas CountyDouglas County: 9.1 inhabitants per km²9.1Whitman CountyWhitman County: 8.6 inhabitants per km²8.6Kittitas CountyKittitas County: 7.9 inhabitants per km²7.9Stevens CountyStevens County: 7.3 inhabitants per km²7.3Jefferson CountyJefferson County: 7.1 inhabitants per km²7.1Wahkiakum CountyWahkiakum County: 6.5 inhabitants per km²6.5Klickitat CountyKlickitat County: 4.7 inhabitants per km²4.7Adams CountyAdams County: 4.1 inhabitants per km²4.1Pend Oreille CountyPend Oreille County: 3.7 inhabitants per km²3.7Okanogan CountyOkanogan County: 3.1 inhabitants per km²3.1Skamania CountySkamania County: 2.8 inhabitants per km²2.8Lincoln CountyLincoln County: 1.8 inhabitants per km²1.8Columbia CountyColumbia County: 1.8 inhabitants per km²1.8Ferry CountyFerry County: 1.3 inhabitants per km²1.3Garfield CountyGarfield County: 1.2 inhabitants per km²1.2
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2020
inhabitants per km²
1King County415
2Clark County310.4
3Kitsap County269.5
4Pierce County213.8
5Island County161
6Thurston County158.2
7Snohomish County153.6
8Spokane County118.4
9Benton County47.1
10Whatcom County41.7
11San Juan County39.6
12Cowlitz County37.6
13Franklin County30.2
14Skagit County29
15Mason County26.6
16Yakima County23.1
17Walla Walla County19
18Clallam County17.2
19Grays Harbor County15.4
20Grant County14.3
21Asotin County13.6
22Lewis County13.3
23Chelan County10.5
24Pacific County9.7
25Douglas County9.1
26Whitman County8.6
27Kittitas County7.9
28Stevens County7.3
29Jefferson County7.1
30Wahkiakum County6.5
31Klickitat County4.7
32Adams County4.1
33Pend Oreille County3.7
34Okanogan County3.1
35Skamania County2.8
36Lincoln County1.8
37Columbia County1.8
38Ferry County1.3
39Garfield County1.2

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 415 inhabitants per km² in 2020, according to the U.S. Census Bureau.

Which county has the lowest population density?

Garfield County, with 1.2 inhabitants per km² in 2020.

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