The U.S. State of Colorado is divided into 64 counties. Two of these, the City and County of Denver, which serves as the state capital, and the City and County of Broomfield, have consolidated city and county governments. Of the other 62 counties, all operate under Dillon's Rule except the two that are home rule (Pitkin and Weld). Counties are important units of government in Colorado since there are no civil townships or other minor civil divisions. El Paso County, with a population of 730,395 in 2020, is the most populous county in Colorado, while San Juan County is the least populous, with a population of 705. Las Animas County, 12369 km2 in area, is the most extensive county, while the City and County of Broomfield, 87 km2 in area, is the least extensive. The City and County of Denver is the most densely populated Colorado county, with a population density of 4,674 residents per square mile (1,805/km2) as of 2020, while Hinsdale County is the least densely populated county, with a population density of 0.71 resident per square mile (0.27/km2). Mount Elbert, the highest summit of Colorado and the entire Rocky Mountains at an elevation of 4401.2 m, is located in Lake County. The lowest point in Colorado is where the Arikaree River flows out of Yuma County and into Kansas, at 1011 m elevation. This point, which is the highest low point of any state, is higher than the highest points of 18 states and the District of Columbia.

History

On November 1, 1861, the new Territory of Colorado created 17 original counties: Arapahoe, Boulder, Clear Creek, Costilla, Douglas, El Paso, Fremont, Gilpin, Guadalupe, Huerfano, Jefferson, Lake, Larimer, Park, Pueblo, Summit, and Weld; plus the Cheyenne Reserve. Six days later, the name of Guadelupe County was changed to Conejos County. On February 9, 1866, the first new county, Las Animas, was created, followed by Saguache in December of that year. Bent County was created in February 1870, followed by Greenwood the following month. On February 2, 1874, Grand County and Elbert County were formed, and on February 10, La Plata, Hinsdale, and Rio Grande counties were created. Greenwood was absorbed into Bent on February 5. The last county to be created under the Colorado Territory name was San Juan County, created three months before statehood. By the time Colorado became a state on August 1, 1876, it had only 26 counties. In January 1877, Routt and Ouray were formed, followed by Gunnison and Custer counties in March. In February 1879, Chaffee County was created. From February 8–10, 1879, Lake county was renamed Carbonate County. In 1881, Dolores County and Pitkin County were created. In 1883, Montrose, Mesa, Garfield, Eagle, Delta, and San Miguel counties were formed, leaving the total number of counties at 39. The number rose to 40 in 1885 with the creation of Archuleta County on April 14. Washington County and Logan County were both created in 1887. Between February 19 and April 16 in 1889, Morgan, Yuma, Cheyenne, Otero, Rio Blanco, Phillips, Sedgwick, Kiowa, Kit Carson, Lincoln, Prowers, Baca, and Montezuma counties were formed, bringing the total to 55. By 1900, Mineral County and Teller County had been added. On November 15, 1902, Arapahoe County was split into Adams and South Arapahoe Counties, and Denver was reconstituted as a consolidated city-county from portions of both newly formed counties on December 1, 1902. By 1912, Jackson County, Moffat County, and Crowley County had been created. Alamosa was created in 1913. In 2001, Broomfield was reconstituted as a consolidated city-county from parts of Adams, Boulder, Jefferson and Weld counties, bringing the total to 64 counties.

List

Select the OpenStreetMap link at the right to view the location of these 64 counties.

2023 population estimates

For United States Census Bureau population estimates for Colorado counties as of July 1, 2023, see the List of Colorado counties by population. That list ranks the counties by 2023 population and includes population changes since the 2000 United States Census. That list also includes the county websites, links to Colorado Department of Transportation county maps, and the geographic coordinates of the counties. As of July 1, 2023, El Paso County remains the most populous county in Colorado with a population estimate of 744,215, while Hinsdale County with a 2023 population of 765 is now the least populous. Five of the 64 Colorado counties now have more than 500,000 residents, while 12 counties have fewer than 5,000 residents.

Former counties

The following sortable table lists all the historic counties of the Territory of New Mexico, the Territory of Utah, the Territory of Kansas, and the extralegal Territory of Jefferson that previously existed within the boundaries of the present State of Colorado, as well as the three defunct counties of the Territory of Colorado and the three defunct counties of the State of Colorado.

County high points

Of the 64 Colorado counties, 20 counties extend above 14000 ft elevation, 32 counties extend above 13000 ft, 42 counties extend above 10000 ft, and all 64 Colorado counties extend above 4116 ft.

County mean elevation

Of Colorado's 64 counties, 4 counties have a mean elevation above 11000 ft elevation, 22 counties have a mean elevation above 10000 ft, 32 counties have a mean elevation above 9000 ft, and all 64 counties have a mean elevation above 3880 ft. The following 13 Colorado counties have highest mean elevation of any county in the United States, exceeding even the Denali Borough of Alaska.

County firsts

County distinctions

Gallery