RANKING · 2020 CENSUS · 39 SHOWN OF 39

Most population gained, Washington counties · 2020

Washington counties that added the most residents from the 2010 census to 2020, by raw count of people rather than percentage. This list covers the 39 counties in Washington that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01King County, WAWA2,344,939+338,426+47%

02Pierce County, WAWA946,288+125,905+10%

03Snohomish County, WAWA870,656+114,622−18%

04Clark County, WAWA532,119+77,948−27%

05Spokane County, WAWA558,344+68,118+20%

06Thurston County, WAWA304,261+42,529−8%

07Benton County, WAWA221,722+31,696+6%

08Whatcom County, WAWA236,392+25,707−34%

09Kitsap County, WAWA283,374+24,478−42%

10Franklin County, WAWA102,612+18,586+57%

11Yakima County, WAWA259,185+13,497−60%

12Skagit County, WAWA132,975+12,622−46%

13Grant County, WAWA105,727+10,003−50%

14Island County, WAWA85,657+8,351−27%

15Cowlitz County, WAWA114,885+8,320−23%

16Lewis County, WAWA88,062+6,694−28%

17Chelan County, WAWA81,941+6,621−54%

18Clallam County, WAWA78,202+5,751−29%

19Mason County, WAWA71,165+5,027−55%

20Douglas County, WAWA46,473+4,507−30%

21Walla Walla County, WAWA62,361+3,803−44%

22Kittitas County, WAWA48,803+3,422−48%

23Whitman County, WAWA48,512+3,197+63%

24Jefferson County, WAWA33,970+3,105−47%

25Stevens County, WAWA49,668+2,914−68%

26Grays Harbor County, WAWA78,144+2,839−6%

27Pacific County, WAWA24,357+2,445+16%

28Klickitat County, WAWA24,331+2,417−5%

29San Juan County, WAWA18,577+2,019−50%

30Adams County, WAWA21,488+1,885−33%

31Okanogan County, WAWA45,230+984−84%

32Skamania County, WAWA12,669+970−39%

33Asotin County, WAWA22,545+662−78%

34Wahkiakum County, WAWA4,873+444−11%

35Pend Oreille County, WAWA14,457+400−86%

36Lincoln County, WAWA11,982+306−77%

37Garfield County, WAWA2,416+20−87%

38Columbia County, WAWA4,141-126−415%

39Ferry County, WAWA7,517-373−139%

SHOWING 1–39 OF 39

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS