Colorado Counties by Population (2025)

2025 Pop.

100K

200K

300K

400K

500K

600K

700K

Top 5 Most Populous Counties

64 Counties

County
2025 Pop. ↓
Area (mi²)
Density
Change (2020)
El Paso County758,6102.1K3573.38%
Denver County736,6711534,8152.65%
Arapahoe County671,9727988422.54%
Jefferson County579,373764758-0.65%
Adams County550,2691.2K4725.72%
Douglas County402,84984147911.8%
Weld County379,2744K9514.42%
Larimer County377,6182.6K1454.91%
Boulder County332,1057264570.35%
Pueblo County170,0092.4K710.98%
Mesa County162,8303.3K494.37%
Broomfield County79,617332,4136.88%
Garfield County63,4132.9K222.61%
La Plata County57,2451.7K342.82%
Eagle County54,0681.7K32-2.87%
Fremont County49,8341.5K321.93%
Montrose County45,2932.2K205.78%
Delta County32,6701.1K295.2%
Summit County30,94060851-0.96%
Morgan County30,7941.3K245.89%
Elbert County29,9521.9K1614.29%
Montezuma County27,0822K134.61%
Routt County25,3322.4K111.98%
Teller County25,013557451.08%
Chaffee County20,9521K217.51%
Logan County20,8501.8K11-1.69%
Park County18,5112.2K86.26%
Otero County17,8341.3K14-4.45%
Gunnison County17,2863.2K52.01%
Alamosa County16,710723232.05%
Pitkin County16,59697117-4.43%
Grand County16,3371.8K93.75%
Las Animas County14,6424.8K30.98%
Archuleta County14,0571.4K104.71%
Moffat County12,9974.7K3-2.05%
Prowers County12,1251.6K70.87%
Rio Grande County11,07091212-4.1%
Yuma County10,1152.4K41.45%
Clear Creek County9,02939523-3.54%
San Miguel County7,7641.3K6-3.6%
Conejos County7,5871.3K61.83%
Lake County7,37137720-0.57%
Kit Carson County7,1282.2K30.92%
Huerfano County6,9351.6K41.63%
Saguache County6,6533.2K24.03%
Rio Blanco County6,6283.2K21.64%
Gilpin County6,003150403.2%
Bent County5,8461.5K46.68%
Lincoln County5,6982.6K20.65%
Crowley County5,5847877-1.78%
Custer County5,555739817.57%
Ouray County5,209541106.7%
Washington County4,6832.5K2-2.72%
Phillips County4,4866887-0.99%
Costilla County3,7481.2K37.06%
Baca County3,3712.6K1-3.19%
Dolores County2,4091.1K23.35%
Sedgwick County2,2095484-7.53%
Cheyenne County1,6861.8K1-3.44%
Kiowa County1,4081.8K1-3.03%
Jackson County1,2301.6K1-10.74%
Mineral County93487617.23%
San Juan County845388219.35%
Hinsdale County7331.1K1-6.86%

Overview of Colorado Counties

There are 64 counties in Colorado.

El Paso County is the largest county in the state, with a population of 758,610. 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:

Colorado Counties with the Fewest Residents

The smallest county in Colorado is Hinsdale County , with a population of just 733. This total represents a decrease of 0.1% since the last census count was performed.

Other small counties include:

Colorado Counties with Rapid Growth

San Juan County , with its current population of 845, has shown the largest population growth, with an increase of 0.2% since the last census.

Adams County has also had relatively high population growth of 0.06% with 550,269 residents.

On the other hand, Jackson County has had the largest decrease in population, with its 1,230 current residents totalling 0.1% less than the previous census.

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)

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