The largest county in New Mexico
There are two right answers. By land area it is Catron County; by population it is Bernalillo County. Which one you want depends on what you meant by largest.
Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025. Retrieved 30 August 2026.
By land area
| Rank | Name | Land area | Population |
|---|---|---|---|
| 1 | Catron County | 6,924 sq mi | 3,827 |
| 2 | Socorro County | 6,646 sq mi | 15,838 |
| 3 | Otero County | 6,613 sq mi | 70,368 |
| 4 | Chaves County | 6,067 sq mi | 63,364 |
| 5 | Rio Arriba County | 5,861 sq mi | 39,832 |
| 6 | San Juan County | 5,517 sq mi | 120,340 |
| 7 | McKinley County | 5,451 sq mi | 68,119 |
| 8 | Lincoln County | 4,831 sq mi | 19,844 |
| 9 | San Miguel County | 4,722 sq mi | 26,260 |
| 10 | Cibola County | 4,540 sq mi | 26,807 |
By population
| Rank | Name | Population | Density |
|---|---|---|---|
| 1 | Bernalillo County | 667,601 | 575 per sq mi |
| 2 | Doña Ana County | 229,091 | 60.2 per sq mi |
| 3 | Sandoval County | 159,565 | 43.0 per sq mi |
| 4 | Santa Fe County | 156,907 | 82.1 per sq mi |
| 5 | San Juan County | 120,340 | 21.8 per sq mi |
| 6 | Valencia County | 82,013 | 76.9 per sq mi |
| 7 | Lea County | 74,749 | 17.0 per sq mi |
| 8 | Otero County | 70,368 | 10.6 per sq mi |
| 9 | McKinley County | 68,119 | 12.5 per sq mi |
| 10 | Chaves County | 63,364 | 10.4 per sq mi |
And the smallest
More on New Mexico
Rebuilt from source data 30 August 2026. How these figures are produced.