Washington counties ranked by the diversity index, the chance that two public school students picked at random from the county belong to different racial or ethnic groups. Counties need at least 3 schools and 1,000 students to qualify. The median ranked county is at 53.5%.
| # | County | State | Diversity index |
|---|---|---|---|
| 1 | King County | WA | 76.2% |
| 2 | Pierce County | WA | 72.2% |
| 3 | Snohomish County | WA | 68.8% |
| 4 | Okanogan County | WA | 67.4% |
| 5 | Thurston County | WA | 63.3% |
| 6 | Kitsap County | WA | 59.4% |
| 7 | Clark County | WA | 58.9% |
| 8 | Mason County | WA | 58.8% |
| 9 | Columbia County | WA | 58.2% |
| 10 | Grays Harbor County | WA | 58.0% |
| 11 | Benton County | WA | 58.0% |
| 12 | Skagit County | WA | 57.8% |
| 13 | Whatcom County | WA | 57.6% |
| 14 | Island County | WA | 57.6% |
| 15 | Clallam County | WA | 57.2% |
| 16 | Walla Walla County | WA | 55.4% |
| 17 | Ferry County | WA | 54.4% |
| 18 | Chelan County | WA | 54.1% |
| 19 | Pacific County | WA | 52.8% |
| 20 | Douglas County | WA | 51.2% |
| 21 | Klickitat County | WA | 50.8% |
| 22 | Grant County | WA | 47.7% |
| 23 | Lewis County | WA | 47.3% |
| 24 | Cowlitz County | WA | 47.0% |
| 25 | San Juan County | WA | 46.2% |
| 26 | Spokane County | WA | 45.6% |
| 27 | Stevens County | WA | 43.3% |
| 28 | Kittitas County | WA | 43.0% |
| 29 | Whitman County | WA | 42.9% |
| 30 | Yakima County | WA | 42.4% |
| 31 | Franklin County | WA | 40.8% |
| 32 | Jefferson County | WA | 39.7% |
| 33 | Asotin County | WA | 36.1% |
| 34 | Pend Oreille County | WA | 35.0% |
| 35 | Adams County | WA | 29.5% |
| 36 | Lincoln County | WA | 29.5% |