The Diversity Index is a scale of 0 to 100 that represents the likelyhood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.
| Name | County | Diversity Index | |
|---|---|---|---|
| 1. | Ryderwood Census Designated Place | Cowlitz | 9.7 |
| 2. | Steptoe Census Designated Place | Whitman | 10.3 |
| 3. | Town of Oakesdale | Whitman | 10.6 |
| 4. | Town of Farmington | Whitman | 11.5 |
| 5. | Town of Ione | Pend Oreille | 12.6 |
| 6. | Town of Metaline Falls | Pend Oreille | 12.6 |
| 7. | Town of Metaline | Pend Oreille | 12.8 |
| 8. | City of Spangle | Spokane | 13.3 |
| 9. | Town of Garfield | Whitman | 13.5 |
| 10. | Town of Creston | Lincoln | 13.6 |
| 11. | Town of Winthrop | Okanogan | 14.7 |
| 12. | Town of Yacolt | Clark | 15.0 |
| 13. | Mineral Census Designated Place | Lewis | 15.0 |
| 14. | Port Ludlow Census Designated Place | Jefferson | 15.5 |
| 15. | Glacier Census Designated Place | Whatcom | 15.5 |
| 16. | Green Bluff Census Designated Place | Spokane | 16.2 |
| 17. | Clarkston Heights-Vineland Census Designated Place | Asotin | 16.4 |
| 18. | City of Roslyn | Kittitas | 16.5 |
| 19. | City of Palouse | Whitman | 16.8 |
| 20. | Town of Cathlamet | Wahkiakum | 16.9 |
