Colorado Counties by Population (2025)

There are 64 counties in Colorado.

El Paso County is the largest county in the state, with a population of 751,453. The most recent census shows that its population has increased by 0.03% since the previous census.

A number of other Colorado counties also boast relatively large populations for their state, though not able to match the density of El Paso County:

• Denver County : 722,825
• Arapahoe County : 655,645

Colorado Counties with the Fewest Residents

The smallest county in Colorado is Hinsdale County , with a population of just 753. This total represents a decrease of 0.0% since the last census count was performed.

Other small counties include:

• San Juan County : 794
• Mineral County : 970
• Kiowa County : 1,284

Colorado Counties with Rapid Growth

Custer County , with its current population of 5,928, has shown the largest population growth, with an increase of 0.3% since the last census.

Adams County has also had relatively high population growth of 0.05% with 545,077 residents.

On the other hand, Kiowa County has had the largest decrease in population, with its 1,284 current residents totalling 0.1% less than the previous census.