New Mexico Counties by Population (2025)

There are 33 counties in New Mexico.

Bernalillo County is the largest county in the state, with a population of 670,922. The most recent census shows that its population has decreased by 0.01% since the previous census.

A number of other New Mexico counties also boast relatively large populations for their state, though not able to match the density of Bernalillo County:

• Doña Ana County : 232,198
• Sandoval County : 159,571

New Mexico Counties with the Fewest Residents

The smallest county in New Mexico is Harding County , with a population of just 627. This total represents a decrease of 0.0% since the last census count was performed.

Other small counties include:

• De Baca County : 1,642
• Catron County : 3,787
• Union County : 3,880

New Mexico Counties with Rapid Growth

Torrance County , with its current population of 16,273, has shown the largest population growth, with an increase of 0.1% since the last census.

Bernalillo County has also had relatively high population growth of -0.01% with 670,922 residents.

On the other hand, Quay County has had the largest decrease in population, with its 8,253 current residents totalling 0.1% less than the previous census.