Washington counties by area
Official, comparable measurements for 39 counties and county equivalents.
Understanding Washington’s county areas
The land-area range runs from San Juan County at 173.9 mi² to Okanogan County at 5,266.2 mi². The largest has 30.3 times the land area of the smallest and accounts for 7.9% of the combined county land in Washington.
The median county-equivalent land area is 1,738.8 mi², above the national median of 604.5 mi². The median describes the middle of the county size distribution; it does not describe how people or development are distributed. A state with a few very large counties can have a much smaller median than its largest entry suggests.
Where water changes the picture
Clallam County has the most assigned water area, at 930.2 mi². San Juan County has the highest water share, with water making up 72% of its total area. Water area and water percentage answer different questions: the first measures an amount, while the second measures the mix of land and water.
Across all 39 entries, water accounts for 6.8% of the combined total area. This is calculated from the summed land and water measurements, rather than averaging county percentages, which would give each small and large county equal weight.
Compare the largest and smallest county equivalents in Washington to see land, water, and total area on the same scale.
These calculations use the 2026 Census county records listed below. County-equivalent boundaries vary between states; area alone does not measure population, density, or usable land. See coverage and calculation rules.
Complete area table
Sorted from largest to smallest land area.
| # | County / equivalent | Land | Water | Water share |
|---|---|---|---|---|
| 1 | Okanogan CountyGEOID 53047 | 5,266.2 mi² | 46.5 mi² | 0.9% |
| 2 | Yakima CountyGEOID 53077 | 4,294.5 mi² | 15.9 mi² | 0.4% |
| 3 | Chelan CountyGEOID 53007 | 2,921.2 mi² | 73.2 mi² | 2.4% |
| 4 | Grant CountyGEOID 53025 | 2,679.6 mi² | 111.9 mi² | 4% |
| 5 | Stevens CountyGEOID 53065 | 2,477.1 mi² | 62.9 mi² | 2.5% |
| 6 | Lewis CountyGEOID 53041 | 2,402.8 mi² | 33.6 mi² | 1.4% |
| 7 | Lincoln CountyGEOID 53043 | 2,310.6 mi² | 29.1 mi² | 1.2% |
| 8 | Kittitas CountyGEOID 53037 | 2,297.3 mi² | 35.7 mi² | 1.5% |
| 9 | Ferry CountyGEOID 53019 | 2,203.2 mi² | 54.2 mi² | 2.4% |
| 10 | Whitman CountyGEOID 53075 | 2,159.3 mi² | 18.6 mi² | 0.9% |
| 11 | King CountyGEOID 53033 | 2,115.8 mi² | 191.7 mi² | 8.3% |
| 12 | Whatcom CountyGEOID 53073 | 2,107.9 mi² | 396.9 mi² | 15.8% |
| 13 | Snohomish CountyGEOID 53061 | 2,086.5 mi² | 109.2 mi² | 5% |
| 14 | Adams CountyGEOID 53001 | 1,925 mi² | 4.8 mi² | 0.2% |
| 15 | Grays Harbor CountyGEOID 53027 | 1,902.3 mi² | 321.3 mi² | 14.5% |
| 16 | Klickitat CountyGEOID 53039 | 1,871.6 mi² | 32.8 mi² | 1.7% |
| 17 | Douglas CountyGEOID 53017 | 1,819.2 mi² | 29.6 mi² | 1.6% |
| 18 | Jefferson CountyGEOID 53031 | 1,803.7 mi² | 384.2 mi² | 17.6% |
| 19 | Spokane CountyGEOID 53063 | 1,764.2 mi² | 16.8 mi² | 0.9% |
| 20 | Clallam CountyGEOID 53009 | 1,738.8 mi² | 930.2 mi² | 34.9% |
| 21 | Skagit CountyGEOID 53057 | 1,730.2 mi² | 186.8 mi² | 9.7% |
| 22 | Benton CountyGEOID 53005 | 1,700.1 mi² | 59.6 mi² | 3.4% |
| 23 | Pierce CountyGEOID 53053 | 1,668 mi² | 137.5 mi² | 7.6% |
| 24 | Skamania CountyGEOID 53059 | 1,658.3 mi² | 28.3 mi² | 1.7% |
| 25 | Pend Oreille CountyGEOID 53051 | 1,400.2 mi² | 25.3 mi² | 1.8% |
| 26 | Walla Walla CountyGEOID 53071 | 1,270 mi² | 28.9 mi² | 2.2% |
| 27 | Franklin CountyGEOID 53021 | 1,241.6 mi² | 23.4 mi² | 1.8% |
| 28 | Cowlitz CountyGEOID 53015 | 1,141.2 mi² | 25.2 mi² | 2.2% |
| 29 | Mason CountyGEOID 53045 | 959.6 mi² | 91.5 mi² | 8.7% |
| 30 | Pacific CountyGEOID 53049 | 933.4 mi² | 293.2 mi² | 23.9% |
| 31 | Columbia CountyGEOID 53013 | 868.6 mi² | 4.9 mi² | 0.6% |
| 32 | Thurston CountyGEOID 53067 | 722.5 mi² | 51.6 mi² | 6.7% |
| 33 | Garfield CountyGEOID 53023 | 710.8 mi² | 7.5 mi² | 1% |
| 34 | Asotin CountyGEOID 53003 | 636.1 mi² | 4.4 mi² | 0.7% |
| 35 | Clark CountyGEOID 53011 | 628.5 mi² | 27.1 mi² | 4.1% |
| 36 | Kitsap CountyGEOID 53035 | 395.1 mi² | 170.7 mi² | 30.2% |
| 37 | Wahkiakum CountyGEOID 53069 | 262.9 mi² | 23.8 mi² | 8.3% |
| 38 | Island CountyGEOID 53029 | 208.7 mi² | 308.6 mi² | 59.7% |
| 39 | San Juan CountyGEOID 53055 | 173.9 mi² | 446.9 mi² | 72% |