RANKING · 1990 CENSUS · 39 SHOWN OF 39

Most densely populated, Washington counties · 1990

Washington counties ranked by residents per square mile (2023). This list covers the 39 counties in Washington that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest growing Fastest shrinking Most sparsely populated Best broadband access Worst broadband access

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01King County, WAWA2,344,939712−13%

02Kitsap County, WAWA283,374480−18%

03Clark County, WAWA532,119379−31%

04Pierce County, WAWA946,288351−16%

05Island County, WAWA85,657289−16%

06Snohomish County, WAWA870,656223−23%

07Thurston County, WAWA304,261223−22%

08Spokane County, WAWA558,344205−14%

09Cowlitz County, WAWA114,88572−12%

10Benton County, WAWA221,72266−21%

11Whatcom County, WAWA236,39261−23%

12San Juan County, WAWA18,57758−29%

13Skagit County, WAWA132,97546−23%

14Yakima County, WAWA259,18544−15%

15Mason County, WAWA71,16540−22%

16Walla Walla County, WAWA62,36138−12%

17Grays Harbor County, WAWA78,14434−4%

18Clallam County, WAWA78,20232−12%

19Franklin County, WAWA102,61230−24%

20Asotin County, WAWA22,54528−14%

21Lewis County, WAWA88,06225−13%

22Grant County, WAWA105,72720−27%

23Pacific County, WAWA24,35720−10%

24Whitman County, WAWA48,51218−5%

25Chelan County, WAWA81,94118−22%

26Douglas County, WAWA46,47314−20%

27Wahkiakum County, WAWA4,87313−13%

28Stevens County, WAWA49,66812−23%

29Kittitas County, WAWA48,80312−20%

30Jefferson County, WAWA33,97011−22%

31Klickitat County, WAWA24,3319−13%

32Adams County, WAWA21,4887−17%

33Pend Oreille County, WAWA14,4576−24%

34Okanogan County, WAWA45,2306−16%

35Skamania County, WAWA12,6695−16%

36Columbia County, WAWA4,1415−1%

37Lincoln County, WAWA11,9824−13%

38Garfield County, WAWA2,4163−6%

39Ferry County, WAWA7,5173−13%

SHOWING 1–39 OF 39

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UPDATED 2026-06-02 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES