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. | Texas County | 75.2 |
| 2. | Harmon County | 74.6 |
| 3. | Tillman County | 72.5 |
| 4. | Oklahoma County | 72.3 |
| 5. | Jackson County | 70.1 |
| 6. | Adair County | 69.5 |
| 7. | Cherokee County | 68.6 |
| 8. | Comanche County | 68.5 |
| 9. | Muskogee County | 67.3 |
| 10. | Caddo County | 67.0 |
| 11. | Marshall County | 66.7 |
| 12. | Tulsa County | 66.2 |
| 13. | Custer County | 64.0 |
| 14. | Beaver County | 63.7 |
| 15. | Choctaw County | 61.9 |
| 16. | Hughes County | 61.3 |
| 17. | McCurtain County | 61.1 |
| 18. | Love County | 60.8 |
| 19. | Harper County | 60.7 |
| 20. | Okmulgee County | 59.9 |
