Der US-Bundesstaat New Mexico ist in 33 Countys unterteilt.
| County | Einwohner 1. Juli 2005 | Verwaltungssitz | Einwohner 1. Juli 2004 |
|---|---|---|---|
| Bernalillo | 603.562 | Albuquerque | 484.246 |
| Catron | 3.409 | Reserve | 345 |
| Chaves | 61.860 | Roswell | 45.074 |
| Cibola | 27.620 | Grants | 9.041 |
| Colfax | 13.755 | Raton | 7.036 |
| Curry | 45.846 | Clovis | 33.063 |
| De Baca | 2.016 | Fort Sumner | 1.078 |
| Doña Ana | 189.444 | Las Cruces | 79.524 |
| Eddy | 51.437 | Carlsbad | 25.417 |
| Grant | 29.747 | Silver City | 9.911 |
| Guadalupe | 4.369 | Santa Rosa | 2.625 |
| Harding | 740 | Mosquero | 102 |
| Hidalgo | 5.139 | Lordsburg | 2.854 |
| Lea | 56.719 | Lovington | 9.553 |
| Lincoln | 21.007 | Carrizozo | 1.053 |
| Los Alamos | 18.822 | Los Alamos | 11.909 (2000) |
| Luna | 26.498 | Deming | 14.647 |
| McKinley | 71.918 | Gallup | 19.715 |
| Mora | 5.107 | Mora | … |
| Otero | 63.538 | Alamogordo | 36.211 |
| Quay | 9.259 | Tucumcari | 5.476 |
| Rio Arriba | 40.828 | Tierra Amarilla | … |
| Roosevelt | 18.238 | Portales | 11.214 |
| San Juan | 126.208 | Aztec | 6.906 |
| San Miguel | 29.530 | Las Vegas | 14.031 |
| Sandoval | 107.460 | Bernalillo | 6.956 |
| Santa Fe | 140.855 | Santa Fe | 68.041 |
| Sierra | 12.815 | Truth or Consequences | 7.163 |
| Socorro | 18.148 | Socorro | 8.724 |
| Taos | 31.722 | Taos | 5.062 |
| Torrance | 17.501 | Estancia | 1.555 |
| Union | 3.850 | Clayton | 2.191 |
| Valencia | 69.417 | Los Lunas | 11.748 |