| County | Rank | Change (2020) ↓ | 2026 Pop. | 2020 Pop. |
|---|---|---|---|---|
| Torrance County | 1 | 9.98% | 16,560 | 15,057 |
| Valencia County | 2 | 9.68% | 83,913 | 76,507 |
| Sandoval County | 3 | 8.09% | 161,385 | 149,301 |
| Doña Ana County | 4 | 6.8% | 235,030 | 220,069 |
| Lea County | 5 | 5.1% | 78,447 | 74,643 |
| Catron County | 6 | 4.71% | 3,779 | 3,609 |
| Luna County | 7 | 4.05% | 26,488 | 25,457 |
| Los Alamos County | 8 | 3.93% | 20,185 | 19,422 |
| Otero County | 9 | 3.77% | 70,425 | 67,866 |
| Santa Fe County | 10 | 3.37% | 160,281 | 155,056 |
| Eddy County | 11 | 1.06% | 63,000 | 62,342 |
| Guadalupe County | 12 | 1.01% | 4,487 | 4,442 |
| Taos County | 13 | 0.04% | 34,478 | 34,465 |
| Colfax County | 14 | -0.45% | 12,297 | 12,353 |
| Rio Arriba County | 15 | -0.61% | 40,023 | 40,268 |
| San Juan County | 16 | -0.62% | 120,637 | 121,387 |
| Bernalillo County | 17 | -1% | 670,097 | 676,882 |
| Cibola County | 18 | -1.46% | 26,576 | 26,969 |
| Lincoln County | 19 | -1.59% | 19,981 | 20,304 |
| Chaves County | 20 | -2.15% | 63,755 | 65,153 |
| Grant County | 21 | -2.18% | 27,599 | 28,214 |
| Curry County | 22 | -3.2% | 46,826 | 48,374 |
| De Baca County | 23 | -3.33% | 1,627 | 1,683 |
| Mora County | 24 | -3.67% | 4,038 | 4,192 |
| Roosevelt County | 25 | -4.03% | 18,381 | 19,153 |
| Sierra County | 26 | -4.05% | 11,097 | 11,565 |
| San Miguel County | 27 | -4.09% | 26,018 | 27,128 |
| Socorro County | 28 | -4.31% | 15,845 | 16,559 |
| Harding County | 29 | -5.35% | 619 | 654 |
| Hidalgo County | 30 | -5.36% | 3,940 | 4,163 |
| McKinley County | 31 | -5.37% | 68,689 | 72,586 |
| Union County | 32 | -5.87% | 3,834 | 4,073 |
| Quay County | 33 | -6.97% | 8,103 | 8,710 |
New Mexico's counties show varied growth patterns from 2020 to 2026. Torrance County leads with 1.6% annualized growth, followed by Valencia County (1.55%) and Sandoval County (1.31%). The largest counties are Bernalillo County (670,097), Doña Ana County (235,030), and Sandoval County (161,385). Of the 33 counties in New Mexico, 13 are growing while 20 have experienced population decline. Overall, counties averaged -0.04% annualized growth, with total population growing by 0.23% annually.
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