County   Created Parent County Seat  Administrator
Adams 1903 Arapahoe Brighton  
Alamosa 1913 Costilla, Conejos Alamosa  
Arapahoe 1861 Original County Littleton  
Archuleta 1885 Conejos Pagosa Springs  
Baca 1889 Las Animas Springfield  
Bent 1874 Greenwood Las Animas  
Boulder 1861 Original County Boulder  
Broomfield 2001 Adams, Boulder, Jefferson, Weld Broomfield  
Chaffee 1879 Lake Salida  
Cheyenne 1889 Bent, Elbert Cheyenne Wells  
Clear Creek 1861 Original County Georgetown  
Conejos 1861 Original County Conejos  
Costilla 1861 Original County San Luis  
Crowley 1911 Bent, Otero Ordway  
Custer 1877 Fremont Westcliffe  
Delta 1883 Gunnison Delta  
Denver 1901 Arapahoe Denver  
Dolores 1881 Ouray Dove Creek  
Douglas 1861 Original County Castle Rock  
Eagle 1883 Summit Eagle  
Elbert 1874 Douglas,  Greenwood Kiowa  
El Paso 1861 Original County Colorado Springs
Fremont 1859 Original County Canon City  
Garfield 1883 Summit Glenwood Springs  
Greenwood 1870 Kit Carson; dissolved 1874; divided between Bent & Elbert Counties   
Gilpin 1861 Original County Central City  
Grand 1874 Summit Hot Sulphur Springs  
Gunnison 1877 Lake Gunnison  
Hinsdale 1874 Conejos Lake City  
Huerfano 1861 Original County Walsenburg  
Jackson 1909 Grand, Larimer Walden  
Jefferson 1861 Original County Golden  
Kiowa 1889 Cheyenne, Bent Eads  
Kit Carson 1889 Elbert Burlington  
Lake 1861 Original County Leadville  
LaPlata 1861 Original County Durango  
Larimer 1861 Original County Fort Collins  
Las Animas 1866 Huerfano Trinidad  
Lincoln 1889 Elbert Hugo  
Logan 1887 Weld Sterling  
Mesa 1883 Gunnison Grand Junction  
Mineral 1892 Hinsdale Creede  
Moffat 1911 Routt Craig  
Montezuma 1889 La Plata Cortez  
Montrose 1883 Gunnison Montrose  
Morgan 1889 Weld Fort Morgan  
Otero 1889 Bent La Junta  
Ouray 1877 Hinsdale,  San Juan Ouray  
Park 1861 Original  County Fairplay  
Phillips 1889 Logan Holyoke  
Pitkin 1881 Gunnison Aspen  
Platte 1872 Weld; dissolved 1874; reverted back to Weld County  
Prowers 1889 Bent Lamar  
Pueblo 1861 Original County Pueblo  
Rio Blanco 1889 Summit Meeker  
Rio Grande 1874 Conejos,  Costilla Del Norte  
Routt 1877 Grand Steamboat Springs  
Saguache 1866 Rio Grande Saguache  
San Juan 1876 La Plata Silverton  
San Miguel 1883 Ouray Telluride  
Sedgwick 1889 Logan Julesburg  
Summit 1861 Original County Breckenridge  
Teller 1899 El Paso Cripple Creek  
Washington 1887 Weld,  Arapahoe Akron  
Weld 1861 Original County Greeley  
Yuma 1889 Washington,  Arapahoe Wray  

 

To adopt any of the above counties contact Colleen Pustola.