List of counties in Colorado

Counties of Colorado
Adams Alam Arapahoe Arch Baca Bent Boul Bro Chaf Cheyenne Cle Conejos Cost Crow Cust Delta Den Dolores Doug Eagle Elbert El Paso Fremont Garfield Gil Grand Gunnison Hins Huerfano Jacks Jef Kiowa Kit Carson Lake La Plata Larimer Las Animas Lincoln Logan Mesa Min Moffat Montez Montrose Morg Otero Our Park Phil Pitkin Prow Pueblo Rio Blanco Rio G Routt Saguache SJ San Miguel Sedg Sum Tell Wash Weld Yuma
Location	State of Colorado
Number	64
Populations	699 (San Juan) – 622,263 (El Paso)
Areas	34 square miles (88 km2) (Broomfield City and County) – 4,773.27 square miles (12,362.7 km2) (Las Animas)
Government	County government
Subdivisions	cities, towns, unincorporated communities, census designated place

The U.S state of Colorado is divided into 64 counties. Counties are important units of government in Colorado since the state has no secondary civil subdivisions, such as townships. Two of these counties, the City and County of Denver and the City and County of Broomfield, have consolidated city and county governments.

Colorado's ISO 3166-2:US state code is CO and its ANSI INCITS 38:2009 state code is 08.

When the Colorado Territory first began creating counties in 1861, 17 counties (Summit, Larimer, Weld, Boulder, Gilpin, Clear Creek, Jefferson, Arapahoe, Douglas, Lake, Conejos, Costilla, Park, Fremont, El Paso, Pueblo, and Huerfano) and a Cheyenne Reserve were formed. In February 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, which was 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 split into Adams in the north and Denver was recognized as a consolidated city-county. By 1912, Jackson County, Moffat County, and Crowley County had been created. Alamosa was created in 1913, and in 2001, Broomfield was recognized as a city-county, bringing a total of 64 counties.