RANKING · 2025 ESTIMATES · 39 SHOWN OF 39

Most densely populated, Washington counties

Washington counties ranked by residents per square mile (2025). This list covers the 39 counties in Washington that qualify, ranked against each other statewide.

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RELATEDLargest by population Fastest growing Fastest shrinking Most population gained Most population lost Most sparsely populated

RANKPLACESTATEPOPPOPULATION DENSITYVS –

01King County, WAWA2,344,9391,108–

02Clark County, WAWA532,119847–

03Kitsap County, WAWA283,374717–

04Pierce County, WAWA946,288567–

05Thurston County, WAWA304,261421–

06Snohomish County, WAWA870,656417–

07Island County, WAWA85,657411–

08Spokane County, WAWA558,344316–

09Benton County, WAWA221,722130–

10Whatcom County, WAWA236,392112–

11San Juan County, WAWA18,577107–

12Cowlitz County, WAWA114,885101–

13Franklin County, WAWA102,61283–

14Skagit County, WAWA132,97577–

15Mason County, WAWA71,16574–

16Yakima County, WAWA259,18560–

17Walla Walla County, WAWA62,36149–

18Clallam County, WAWA78,20245–

19Grays Harbor County, WAWA78,14441–

20Grant County, WAWA105,72739–

21Lewis County, WAWA88,06237–

22Asotin County, WAWA22,54535–

23Chelan County, WAWA81,94128–

24Pacific County, WAWA24,35726–

25Douglas County, WAWA46,47326–

26Whitman County, WAWA48,51222–

27Kittitas County, WAWA48,80321–

28Stevens County, WAWA49,66820–

29Jefferson County, WAWA33,97019–

30Wahkiakum County, WAWA4,87319–

31Klickitat County, WAWA24,33113–

32Adams County, WAWA21,48811–

33Pend Oreille County, WAWA14,45710–

34Okanogan County, WAWA45,2309–

35Skamania County, WAWA12,6698–

36Lincoln County, WAWA11,9825–

37Columbia County, WAWA4,1415–

38Ferry County, WAWA7,5173–

39Garfield County, WAWA2,4163–

SHOWING 1–39 OF 39

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU POPULATION ESTIMATES