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. | San Juan County | 59.8 |
| 2. | Salt Lake County | 56.7 |
| 3. | Weber County | 51.0 |
| 4. | Wasatch County | 48.7 |
| 5. | Utah County | 45.1 |
| 6. | Washington County | 43.0 |
| 7. | Millard County | 42.8 |
| 8. | Beaver County | 38.6 |
| 9. | Grand County | 38.3 |
| 10. | Cache County | 38.0 |
| 11. | Uintah County | 37.5 |
| 12. | Tooele County | 37.0 |
| 13. | Davis County | 35.7 |
| 14. | Duchesne County | 35.0 |
| 15. | Carbon County | 34.8 |
| 16. | Summit County | 34.7 |
| 17. | Sanpete County | 33.3 |
| 18. | Iron County | 31.8 |
| 19. | Box Elder County | 31.2 |
| 20. | Garfield County | 25.1 |
