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.
| County | Diversity Index | |
|---|---|---|
| 1. | Lemhi County | 15.3 |
| 2. | Bonner County | 16.4 |
| 3. | Bear Lake County | 16.5 |
| 4. | Custer County | 16.6 |
| 5. | Oneida County | 16.7 |
| 6. | Butte County | 18.5 |
| 7. | Shoshone County | 19.2 |
| 8. | Valley County | 19.9 |
| 9. | Adams County | 20.1 |
| 10. | Caribou County | 20.7 |
| 11. | Clearwater County | 21.3 |
| 12. | Idaho County | 21.5 |
| 13. | Kootenai County | 21.7 |
| 14. | Boise County | 21.8 |
| 15. | Boundary County | 21.9 |
| 16. | Franklin County | 23.8 |
| 17. | Camas County | 25.3 |
| 18. | Latah County | 25.7 |
| 19. | Nez Perce County | 28.1 |
| 20. | Gem County | 29.3 |
