| County | Rank | Change (2020) ↓ | 2025 Pop. | 2020 Pop. |
|---|---|---|---|---|
| Catron County | 1 | 7.85% | 3,889 | 3,606 |
| Sandoval County | 2 | 7.59% | 160,614 | 149,290 |
| Torrance County | 3 | 7.11% | 16,133 | 15,062 |
| Valencia County | 4 | 6.08% | 81,021 | 76,374 |
| Doña Ana County | 5 | 3.87% | 228,570 | 220,060 |
| Otero County | 6 | 2.37% | 69,471 | 67,862 |
| Los Alamos County | 7 | 1.9% | 19,786 | 19,418 |
| Santa Fe County | 8 | 0.84% | 156,346 | 155,043 |
| Sierra County | 9 | -0.4% | 11,516 | 11,562 |
| San Juan County | 10 | -0.4% | 120,887 | 121,376 |
| Colfax County | 11 | -1.06% | 12,221 | 12,352 |
| Bernalillo County | 12 | -1.18% | 668,844 | 676,853 |
| Taos County | 13 | -1.24% | 34,035 | 34,463 |
| Rio Arriba County | 14 | -1.55% | 39,646 | 40,271 |
| Cibola County | 15 | -1.86% | 26,598 | 27,101 |
| Roosevelt County | 16 | -2.63% | 18,645 | 19,148 |
| Quay County | 17 | -2.75% | 8,472 | 8,712 |
| Mora County | 18 | -2.77% | 4,075 | 4,191 |
| Eddy County | 19 | -3.07% | 60,419 | 62,333 |
| Curry County | 20 | -3.23% | 46,806 | 48,370 |
| San Miguel County | 21 | -3.43% | 26,200 | 27,131 |
| Chaves County | 22 | -3.45% | 62,899 | 65,149 |
| Union County | 23 | -3.51% | 3,928 | 4,071 |
| Luna County | 24 | -3.52% | 24,562 | 25,458 |
| Harding County | 25 | -3.52% | 630 | 653 |
| Lea County | 26 | -4.05% | 71,617 | 74,642 |
| Grant County | 27 | -4.17% | 27,030 | 28,205 |
| Guadalupe County | 28 | -4.39% | 4,244 | 4,439 |
| Lincoln County | 29 | -4.46% | 19,401 | 20,307 |
| Socorro County | 30 | -5.34% | 15,667 | 16,551 |
| De Baca County | 31 | -5.59% | 1,587 | 1,681 |
| Hidalgo County | 32 | -6.99% | 3,873 | 4,164 |
| McKinley County | 33 | -8.35% | 66,529 | 72,590 |
New Mexico's counties show varied growth patterns from 2020 to 2025. Catron County leads with 7.85% annualized growth, followed by Sandoval County (7.59%) and Torrance County (7.11%). The largest counties are Bernalillo County (668,844), Doña Ana County (228,570), and Sandoval County (160,614). Of the 33 counties in New Mexico, 8 are growing while 25 have experienced population decline. Overall, counties averaged -1.37% annualized growth, with total population growing by -0.11% annually.