| County | Rank | Change (2020) ↓ | 2025 Pop. | 2020 Pop. |
|---|---|---|---|---|
| Pinal County | 1 | 21.49% | 522,643 | 430,187 |
| Yuma County | 2 | 7.9% | 221,915 | 205,659 |
| Yavapai County | 3 | 7.41% | 254,783 | 237,217 |
| Mohave County | 4 | 7.03% | 229,236 | 214,185 |
| Graham County | 5 | 5.91% | 40,931 | 38,646 |
| Santa Cruz County | 6 | 5.03% | 50,114 | 47,712 |
| Maricopa County | 7 | 4.52% | 4,645,947 | 4,445,059 |
| La Paz County | 8 | 2.96% | 17,060 | 16,569 |
| Navajo County | 9 | 2.96% | 109,925 | 106,763 |
| Pima County | 10 | 2.81% | 1,074,534 | 1,045,175 |
| Gila County | 11 | 1.53% | 54,165 | 53,351 |
| Coconino County | 12 | -0.15% | 144,970 | 145,192 |
| Greenlee County | 13 | -0.79% | 9,453 | 9,528 |
| Cochise County | 14 | -2.06% | 122,946 | 125,527 |
| Apache County | 15 | -2.84% | 64,042 | 65,913 |
Arizona's counties show varied growth patterns from 2020 to 2025. Pinal County leads with 21.49% annualized growth, followed by Yuma County (7.9%) and Yavapai County (7.41%). The largest counties are Maricopa County (4,645,947), Pima County (1,074,534), and Pinal County (522,643). Of the 15 counties in Arizona, 11 are growing while 4 have experienced population decline. Overall, counties averaged 4.25% annualized growth, with total population growing by 5.23% annually.