Maine counties ranked by the diversity index, the chance that two public school students picked at random from the county belong to different racial or ethnic groups. Counties need at least 3 schools and 1,000 students to qualify. The median ranked county is at 17.6%.
| # | County | State | Diversity index |
|---|---|---|---|
| 1 | Androscoggin County | ME | 44.3% |
| 2 | Cumberland County | ME | 40.1% |
| 3 | Washington County | ME | 31.9% |
| 4 | York County | ME | 25.5% |
| 5 | Aroostook County | ME | 21.7% |
| 6 | Penobscot County | ME | 21.2% |
| 7 | Hancock County | ME | 19.8% |
| 8 | Kennebec County | ME | 18.5% |
| 9 | Sagadahoc County | ME | 16.6% |
| 10 | Oxford County | ME | 15.0% |
| 11 | Waldo County | ME | 14.6% |
| 12 | Knox County | ME | 13.5% |
| 13 | Lincoln County | ME | 13.0% |
| 14 | Somerset County | ME | 12.8% |
| 15 | Piscataquis County | ME | 12.3% |
| 16 | Franklin County | ME | 12.3% |