What are the largest counties in Washington?

King County is the largest county in Washington, with 2,344,939 residents in 2025 (Census PEP). Pierce County (946,288) and Snohomish County (870,656) come next.

Data as of 2025 · updated November 5, 2026

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All 39 ranked Washington counties

Washington counties ranked by population
Rank	County	Residents 2025	Change 2020–25
1	King County	2,344,939	+3.1%
2	Pierce County	946,288	+2.5%
3	Snohomish County	870,656	+4.9%
4	Spokane County	558,344	+3.2%
5	Clark County	532,119	+5.3%
6	Thurston County	304,261	+2.8%
7	Kitsap County	283,374	+2.7%
8	Yakima County	259,185	+1.0%
9	Whatcom County	236,392	+3.9%
10	Benton County	221,722	+6.9%
11	Skagit County	132,975	+2.4%
12	Cowlitz County	114,885	+3.5%
13	Grant County	105,727	+6.3%
14	Franklin County	102,612	+5.6%
15	Lewis County	88,062	+6.7%
16	Island County	85,657	−1.5%
17	Chelan County	81,941	+3.3%
18	Clallam County	78,202	+1.1%
19	Grays Harbor County	78,144	+3.0%
20	Mason County	71,165	+7.8%
21	Walla Walla County	62,361	−0.4%
22	Stevens County	49,668	+6.6%
23	Kittitas County	48,803	+4.2%
24	Whitman County	48,512	+1.5%
25	Douglas County	46,473	+8.0%
26	Okanogan County	45,230	+7.3%
27	Jefferson County	33,970	+2.7%
28	Pacific County	24,357	+3.6%
29	Klickitat County	24,331	+6.6%
30	Asotin County	22,545	+1.0%
31	Adams County	21,488	+4.3%
32	San Juan County	18,577	+4.2%
33	Pend Oreille County	14,457	+7.0%
34	Skamania County	12,669	+5.2%
35	Lincoln County	11,982	+9.7%
36	Ferry County	7,517	+4.4%
37	Wahkiakum County	4,873	+9.6%
38	Columbia County	4,141	+4.7%
39	Garfield County	2,416	+5.2%

How this is ranked

The Census Bureau's July 1 resident population estimates for 2025, largest first, with the change since 2020. Counties with fewer than 1,000 residents are not ranked. Areas without an estimate for the same year as the others are not ranked.

Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025). Figures come from public federal statistics and are informational only, not investment advice. Check the source before relying on a number. Methodology: how ranks and figures are built.

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Questions

What is the largest county in Washington?

King County is the largest county in Washington, with 2,344,939 residents in 2025 (Census PEP). Pierce County (946,288) and Snohomish County (870,656) come next.

How is this ranking calculated?

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