| County Name | Population | State | Rank |
|---|---|---|---|
| Maricopa County | 3,817,117 | Arizona | 1 |
| Pima County | 980,263 | Arizona | 2 |
| Pinal County | 375,770 | Arizona | 3 |
| Yavapai County | 211,033 | Arizona | 4 |
| Mohave County | 200,186 | Arizona | 5 |
| Yuma County | 195,751 | Arizona | 6 |
| Coconino County | 134,421 | Arizona | 7 |
| Cochise County | 131,346 | Arizona | 8 |
| Navajo County | 107,449 | Arizona | 9 |
| Apache County | 71,518 | Arizona | 10 |
| Gila County | 53,597 | Arizona | 11 |
| Santa Cruz County | 47,420 | Arizona | 12 |
| Graham County | 37,220 | Arizona | 13 |
| La Paz County | 20,489 | Arizona | 14 |
| Greenlee County | 8,437 | Arizona | 15 |