There are a total of 64 counties in the state of Colorado. Among them, Arapahoe County is the oldest one (established in 1861) while Broomfield is the youngest (established in 2001). With population of 622,263, El Paso County is the most populated. The biggest county by land area is Las Animas County (12,363 km2) and the smallest is Broomfield (87 km2). Below please see all Colorado counties which are listed in alphabetical order.
- Adams County, CO
- Alamosa County, CO
- Arapahoe County, CO
- Archuleta County, CO
- Baca County, CO
- Bent County, CO
- Boulder County, CO
- City and County of Broomfield, CO
- Chaffee County, CO
- Cheyenne County, CO
- Clear Creek County, CO
- Conejos County, CO
- Costilla County, CO
- Crowley County, CO
- Custer County, CO
- Delta County, CO
- City and County of Denver, CO
- Dolores County, CO
- Douglas County, CO
- Eagle County, CO
- Elbert County, CO
- El Paso County, CO
- Fremont County, CO
- Garfield County, CO
- Gilpin County, CO
- Grand County, CO
- Gunnison County, CO
- Hinsdale County, CO
- Huerfano County, CO
- Jackson County, CO
- Jefferson County, CO
- Kiowa County, CO
- Kit Carson County, CO
- Lake County, CO
- La Plata County, CO
- Larimer County, CO
- Las Animas County, CO
- Lincoln County, CO
- Logan County, CO
- Mesa County, CO
- Mineral County, CO
- Moffat County, CO
- Montezuma County, CO
- Montrose County, CO
- Morgan County, CO
- Otero County, CO
- Ouray County, CO
- Park County, CO
- Phillips County, CO
- Pitkin County, CO
- Prowers County, CO
- Pueblo County, CO
- Rio Blanco County, CO
- Rio Grande County, CO
- Routt County, CO
- Saguache County, CO
- San Juan County, CO
- San Miguel County, CO
- Sedgwick County, CO
- Summit County, CO
- Teller County, CO
- Washington County, CO
- Weld County, CO
- Yuma County, CO
Map of Colorado Counties
