4 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Farmington | 1 | 46,203 | 46,497 | -0.13% | 1,341 | 34 | City |
| Bloomfield | 2 | 7,351 | 7,411 | -0.16% | 396 | 19 | City |
| Aztec | 3 | 6,111 | 6,200 | -0.29% | 358 | 17 | City |
| Kirtland | 4 | 572 | 582 | -0.35% | 332 | 2 | Town |
Farmington is the largest city in San Juan County, with a population of 46,203.
Kirtland is the smallest city in San Juan County, with a population of 572.
There are 4 cities in San Juan County, New Mexico.