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. | Washington County | 22.0 |
| 2. | Cumberland County | 20.2 |
| 3. | Androscoggin County | 20.0 |
| 4. | Penobscot County | 13.6 |
| 5. | York County | 13.3 |
| 6. | Aroostook County | 13.1 |
| 7. | Sagadahoc County | 12.5 |
| 8. | Hancock County | 12.2 |
| 9. | Kennebec County | 12.2 |
| 10. | Waldo County | 11.2 |
| 11. | Piscataquis County | 11.0 |
| 12. | Oxford County | 10.9 |
| 13. | Knox County | 10.9 |
| 14. | Franklin County | 9.6 |
| 15. | Somerset County | 9.6 |
| 16. | Lincoln County | 9.5 |
