List of counties in Colorado
The U.S. state of Colorado is divided into 64 counties. Counties are important units of government in Colorado since there are no townships or other minor civil divisions. Two of these counties, Broomfield and Denver, have consolidated city and county governments.
Colorado's state code is CO and its state code is 08.
When the Colorado Territory first began creating counties in 1861, 17 counties 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, 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 consolidated as a 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, and in 2001, Broomfield was recognized as a city-county, bringing the total to 64 counties.
Counties
Table 2
The following sortable table lists the 64 counties of the state of Colorado with the following information:- The official name of the county,
- The International Committee for Information Technology Standards county code.
- The date the county was established,
- The county seat,
- The rank among the 64 counties of Colorado by population as of July 1, 2013, as estimated by the United States Census Bureau,
- The county population as of July 1, 2013, as estimated by the United States Census Bureau,
- The county population as of April 1, 2010, as enumerated by the 2010 United States Census,
- The percent population change from April 1, 2010, to July 1, 2013,
- A link to a detailed transportation map of the county.
- The average population density per land area of the county as of July 1, 2012,
- The land area of the county,
- The water area of the county,
- The total area of the county,
- The maximum surface elevation in the county,
- The minimum surface elevation in the county,
- The reference latitude of the county, and
- The reference longitude of the county.
| County | INCITS | Date Established | County Seat | Pop Rank | 2013 Pop | 2010 Census | Pop Change | Map | Pop Density | Land Area | Water Area | Total Area | Max Elev | Min Elev | Latitude | Longitude |
| Adams County | 08001 | 1902-11-15 | Brighton | 5 | 393.6 mi−2 152.0 km−2 | 1,167.653 mi2 3,024.208 km2 | 16.243 mi2 42.070 km2 | 1,183.897 mi2 3,066.278 km2 | 5,668 ft 1728 m | 4,432 ft 1351 m | 39.87° N | 104.33° W | - | - | ||
| Alamosa County | 08003 | 1913-03-08 | Alamosa | 29 | 21.4 mi−2 8.3 km−2 | 722.643 mi2 1,871.637 km2 | 0.698 mi2 1.808 km2 | 723.341 mi2 1,873.445 km2 | 14,351 ft 4374 m | 6,387 ft 1947 m | 37.57° N | 105.79° W | - | - | ||
| Arapahoe County | 08005 | 1861-11-01 | Littleton | 3 | 716.7 mi−2 276.7 km−2 | 798.100 mi2 2,067.070 km2 | 7.337 mi2 19.004 km2 | 805.438 mi2 2,086.074 km2 | 6,218 ft 1895 m | 4,730 ft 1442 m | 39.64° N | 104.33° W | - | - | ||
| Archuleta County | 08007 | 1885-04-14 | Pagosa Springs | 36 | 8.9 mi−2 3.5 km−2 | 1,350.175 mi2 3,496.938 km2 | 5.339 mi2 13.828 km2 | 1,355.514 mi2 3,510.765 km2 | 13,308 ft 4056 m | 6,085 ft 1855 m | 37.20° N | 107.05° W | - | - | ||
| Baca County | 08009 | 1889-04-16 | Springfield | 55 | 1.5 mi−2 0.6 km−2 | 2,554.967 mi2 6,617.334 km2 | 2.372 mi2 6.142 km2 | 2,557.338 mi2 6,623.476 km2 | 5,293 ft 1613 m | 3,458 ft 1054 m | 37.30° N | 102.54° W | - | - | ||
| Bent County | 08011 | 1870-02-11 | Las Animas | 47 | 4.3 mi−2 1.7 km−2 | 1,512.861 mi2 3,918.292 km2 | 28.222 mi2 73.094 km2 | 1,541.083 mi2 3,991.386 km2 | 4,857 ft 1481 m | 3,671 ft 1119 m | 37.93° N | 103.08° W | - | - | ||
| Boulder County | 08013 | 1861-11-01 | Boulder | 7 | 405.6 mi−2 156.6 km−2 | 726.289 mi2 1,881.080 km2 | 14.081 mi2 36.469 km2 | 740.370 mi2 1,917.549 km2 | 14,259 ft 4346 m | 4,717 ft 1438 m | 40.09° N | 105.40° W | - | - | ||
| City and County of Broomfield | 08014 | 2001-11-15 | Broomfield | 12 | 1,691.9 mi−2 653.2 km−2 | 33.034 mi2 85.558 km2 | 0.566 mi2 1.466 km2 | 33.600 mi2 87.024 km2 | 5,848 ft 1783 m | 4,691 ft 1430 m | 39.95° N | 105.05° W | - | - | ||
| Chaffee County | 08015 | 1879-02-10 | Salida | 27 | 17.6 mi−2 6.8 km−2 | 1,013.403 mi2 2,624.702 km2 | 1.550 mi2 4.013 km2 | 1,014.953 mi2 2,628.716 km2 | 14,427 ft 4397 m | 5,298 ft 1615 m | 38.74° N | 106.32° W | - | - | ||
| Cheyenne County | 08017 | 1889-03-25 | Cheyenne Wells | 59 | 1.0 mi−2 0.4 km−2 | 1,778.276 mi2 4,605.713 km2 | 3.153 mi2 8.166 km2 | 1,781.429 mi2 4,613.879 km2 | 5,257 ft 1602 m | 3,740 ft 1140 m | 38.84° N | 102.60° W | - | - | ||
| Clear Creek County | 08019 | 1861-11-01 | Georgetown | 39 | 23.0 mi−2 8.9 km−2 | 395.227 mi2 1,023.633 km2 | 1.266 mi2 3.280 km2 | 396.493 mi2 1,026.913 km2 | 14,278 ft 4352 m | 5,075 ft 1547 m | 39.69° N | 105.67° W | - | - | ||
| Conejos County | 08021 | 1861-11-07 | Conejos | 40 | 6.4 mi−2 2.5 km−2 | 1,287.391 mi2 3,334.326 km2 | 3.566 mi2 9.235 km2 | 1,290.956 mi2 3,343.561 km2 | 13,179 ft 4017 m | 7,404 ft 2257 m | 37.21° N | 106.18° W | - | - | ||
| Costilla County | 08023 | 1861-11-01 | San Luis | 56 | 2.9 mi−2 1.1 km−2 | 1,226.952 mi2 3,177.790 km2 | 3.409 mi2 8.829 km2 | 1,230.360 mi2 3,186.619 km2 | 14,351 ft 4374 m | 7,375 ft 2248 m | 37.28° N | 105.43° W | - | - | ||
| Crowley County | 08025 | 1911-05-29 | Ordway | 50 | 7.4 mi−2 2.9 km−2 | 787.421 mi2 2,039.411 km2 | 12.908 mi2 33.430 km2 | 800.329 mi2 2,072.842 km2 | 5,228 ft 1593 m | 3,966 ft 1209 m | 38.32° N | 103.79° W | - | - | ||
| Custer County | 08027 | 1877-03-09 | Westcliffe | 54 | 5.8 mi−2 2.2 km−2 | 738.625 mi2 1,913.031 km2 | 1.299 mi2 3.365 km2 | 739.925 mi2 1,916.396 km2 | 14,246 ft 4342 m | 4,547 ft 1386 m | 38.10° N | 105.37° W | - | - | ||
| Delta County | 08029 | 1883-02-11 | Delta | 18 | 27.1 mi−2 10.5 km−2 | 1,142.050 mi2 2,957.897 km2 | 6.549 mi2 16.961 km2 | 1,148.599 mi2 2,974.858 km2 | 11,396 ft 3474 m | 4,763 ft 1452 m | 38.86° N | 107.86° W | - | - | ||
| City and County of Denver | 08031 | 1902-12-01 | Denver | 2 | 3,922.6 mi−2 1,514.5 km−2 | 153.000 mi2 396.269 km2 | 1.631 mi2 4.225 km2 | 154.632 mi2 400.494 km2 | 5,688 ft 1734 m | 4,803 ft 1464 m | 39.76° N | 104.88° W | - | - | ||
| Dolores County | 08033 | 1881-03-04 | Dove Creek | 58 | 1.9 mi−2 0.7 km−2 | 1,067.051 mi2 2,763.650 km2 | 1.049 mi2 2.716 km2 | 1,068.100 mi2 2,766.366 km2 | 14,252 ft 4344 m | 4,911 ft 1497 m | 37.75° N | 108.53° W | - | - | ||
| Douglas County | 08035 | 1861-11-01 | Castle Rock | 8 | 339.7 mi−2 131.2 km−2 | 840.248 mi2 2,176.232 km2 | 2.621 mi2 6.789 km2 | 842.869 mi2 2,183.022 km2 | 9,836 ft 2998 m | 5,242 ft 1598 m | 39.33° N | 104.93° W | - | - | ||
| Eagle County | 08037 | 1883-02-11 | Eagle | 15 | 31.0 mi−2 12.0 km−2 | 1,684.530 mi2 4,362.912 km2 | 7.261 mi2 18.806 km2 | 1,691.791 mi2 4,381.718 km2 | 14,011 ft 4271 m | 6,220 ft 1896 m | 39.63° N | 106.69° W | - | - | ||
| Elbert County | 08039 | 1874-02-02 | Kiowa | 22 | 12.5 mi−2 4.8 km−2 | 1,850.847 mi2 4,793.671 km2 | 0.171 mi2 0.442 km2 | 1,851.018 mi2 4,794.113 km2 | 7,374 ft 2248 m | 4,580 ft 1396 m | 39.31° N | 104.12° W | - | - | ||
| El Paso County | 08041 | 1861-11-01 | Colorado Springs | 1 | 292.6 mi−2 113.0 km−2 | 2,126.801 mi2 5,508.390 km2 | 2.746 mi2 7.112 km2 | 2,129.547 mi2 5,515.501 km2 | 14,115 ft 4302 m | 5,055 ft 1541 m | 38.83° N | 104.53° W | - | - | ||
| Fremont County | 08043 | 1861-11-01 | Cañon City | 16 | 30.5 mi−2 11.8 km−2 | 1,533.068 mi2 3,970.627 km2 | 0.863 mi2 2.235 km2 | 1,533.931 mi2 3,972.863 km2 | 13,110 ft 3996 m | 4,573 ft 1394 m | 38.46° N | 105.42° W | - | - | ||
| Garfield County | 08045 | 1883-02-10 | Glenwood Springs | 13 | 19.1 mi−2 7.4 km−2 | 2,947.563 mi2 7,634.154 km2 | 8.274 mi2 21.431 km2 | 2,955.838 mi2 7,655.584 km2 | 12,361 ft 3768 m | 4,471 ft 1363 m | 39.60° N | 107.91° W | - | - | ||
| Gilpin County | 08047 | 1861-11-01 | Central City | 48 | 36.3 mi−2 14.0 km−2 | 149.896 mi2 388.229 km2 | 0.364 mi2 0.942 km2 | 150.260 mi2 389.171 km2 | 13,300 ft 4054 m | 4,983 ft 1519 m | 39.86° N | 105.53° W | - | - | ||
| Grand County | 08049 | 1874-02-02 | Hot Sulphur Springs | 33 | 8.0 mi−2 3.1 km−2 | 1,846.330 mi2 4,781.972 km2 | 23.263 mi2 60.250 km2 | 1,869.592 mi2 4,842.222 km2 | 13,559 ft 4133 m | 6,040 ft 1841 m | 40.12° N | 106.10° W | - | - | ||
| Gunnison County | 08051 | 1877-03-09 | Gunnison | 31 | 4.7 mi−2 1.8 km−2 | 3,239.099 mi2 8,389.229 km2 | 20.530 mi2 53.172 km2 | 3,259.629 mi2 8,442.401 km2 | 14,279 ft 4352 m | 7,178 ft 2188 m | 38.67° N | 107.08° W | - | - | ||
| Hinsdale County | 08053 | 1874-02-10 | Lake City | 62 | 0.8 mi−2 0.3 km−2 | 1,117.251 mi2 2,893.668 km2 | 5.917 mi2 15.325 km2 | 1,123.168 mi2 2,908.992 km2 | 14,321 ft 4365 m | 7,299 ft 2225 m | 37.81° N | 107.38° W | - | - | ||
| Huerfano County | 08055 | 1861-11-01 | Walsenburg | 45 | 4.2 mi−2 1.6 km−2 | 1,591.001 mi2 4,120.673 km2 | 2.236 mi2 5.792 km2 | 1,593.237 mi2 4,126.465 km2 | 14,326 ft 4366 m | 4,445 ft 1355 m | 37.69° N | 104.96° W | - | - | ||
| Jackson County | 08057 | 1909-05-05 | Walden | 61 | 0.9 mi−2 0.3 km−2 | 1,613.723 mi2 4,179.523 km2 | 7.239 mi2 18.750 km2 | 1,620.962 mi2 4,198.273 km2 | 12,954 ft 3948 m | 4,865 ft 1483 m | 40.66° N | 106.33° W | - | - | ||
| Jefferson County | 08059 | 1861-11-01 | Golden | 4 | 699.5 mi−2 270.1 km−2 | 764.208 mi2 1,979.290 km2 | 9.825 mi2 25.446 km2 | 774.033 mi2 2,004.736 km2 | 11,589 ft 3532 m | 4,986 ft 1520 m | 39.59° N | 105.25° W | - | - | ||
| Kiowa County | 08061 | 1889-04-11 | Eads | 60 | 0.8 mi−2 0.3 km−2 | 1,767.767 mi2 4,578.496 km2 | 18.160 mi2 47.033 km2 | 1,785.927 mi2 4,625.529 km2 | 4,697 ft 1432 m | 3,687 ft 1124 m | 38.39° N | 102.76° W | - | - | ||
| Kit Carson County | 08063 | 1889-04-11 | Burlington | 41 | 3.8 mi−2 1.5 km−2 | 2,160.822 mi2 5,596.502 km2 | 0.869 mi2 2.252 km2 | 2,161.691 mi2 5,598.754 km2 | 5,297 ft 1615 m | 3,523 ft 1074 m | 39.31° N | 102.60° W | - | - | ||
| Lake County | 08065 | 1861-11-01 | Leadville | 43 | 19.4 mi−2 7.5 km−2 | 376.911 mi2 976.194 km2 | 6.998 mi2 18.124 km2 | 383.909 mi2 994.319 km2 | 14,440 ft 4401 m | 8,720 ft 2658 m | 39.20° N | 106.35° W | - | - | ||
| La Plata County | 08067 | 1874-02-10 | Durango | 14 | 30.3 mi−2 11.7 km−2 | 1,692.078 mi2 4,382.463 km2 | 7.629 mi2 19.760 km2 | 1,699.708 mi2 4,402.223 km2 | 14,093 ft 4296 m | 4,268 ft 1301 m | 37.29° N | 107.84° W | - | - | ||
| Larimer County | 08069 | 1861-11-01 | Fort Collins | 6 | 115.4 mi−2 44.6 km−2 | 2,596.002 mi2 6,723.613 km2 | 37.952 mi2 98.295 km2 | 2,633.954 mi2 6,821.909 km2 | 13,573 ft 4137 m | 4,557 ft 1389 m | 40.66° N | 105.48° W | - | - | ||
| Las Animas County | 08071 | 1866-02-09 | Trinidad | 32 | 3.2 mi−2 1.3 km−2 | 4,772.671 mi2 12,361.162 km2 | 2.676 mi2 6.930 km2 | 4,775.347 mi2 12,368.092 km2 | 13,631 ft 4155 m | 4,317 ft 1316 m | 37.32° N | 104.04° W | - | - | ||
| Lincoln County | 08073 | 1889-04-11 | Hugo | 49 | 2.1 mi−2 0.8 km−2 | 2,577.626 mi2 6,676.021 km2 | 8.796 mi2 22.781 km2 | 2,586.422 mi2 6,698.802 km2 | 5,973 ft 1821 m | 3,923 ft 1196 m | 38.99° N | 103.51° W | - | - | ||
| Logan County | 08075 | 1887-02-25 | Sterling | 25 | 12.4 mi−2 4.8 km−2 | 1,838.546 mi2 4,761.813 km2 | 6.318 mi2 16.364 km2 | 1,844.864 mi2 4,778.177 km2 | 4,947 ft 1508 m | 3,428 ft 1045 m | 40.73° N | 103.09° W | - | - | ||
| Mesa County | 08077 | 1883-02-14 | Grand Junction | 11 | 44.1 mi−2 17.0 km−2 | 3,328.974 mi2 8,622.003 km2 | 12.149 mi2 31.467 km2 | 3,341.123 mi2 8,653.470 km2 | 11,236 ft 3425 m | 4,337 ft 1322 m | 39.02° N | 108.46° W | - | - | ||
| Mineral County | 08079 | 1893-03-27 | Creede | 63 | 0.8 mi−2 0.3 km−2 | 875.666 mi2 2,267.966 km2 | 2.016 mi2 5.222 km2 | 877.683 mi2 2,273.188 km2 | 13,902 ft 4237 m | 7,549 ft 2301 m | 37.65° N | 106.93° W | - | - | ||
| Moffat County | 08081 | 1911-02-27 | Craig | 34 | 2.9 mi−2 1.1 km−2 | 4,743.290 mi2 12,285.065 km2 | 7.622 mi2 19.742 km2 | 4,750.912 mi2 12,304.807 km2 | 10,840 ft 3304 m | 4,993 ft 1522 m | 40.57° N | 108.20° W | - | - | ||
| Montezuma County | 08083 | 1889-04-16 | Cortez | 21 | 12.6 mi−2 4.9 km−2 | 2,029.527 mi2 5,256.451 km2 | 10.624 mi2 27.517 km2 | 2,040.151 mi2 5,283.968 km2 | 13,237 ft 4035 m | 4,639 ft 1414 m | 37.34° N | 108.60° W | - | - | ||
| Montrose County | 08085 | 1883-02-11 | Montrose | 17 | 18.4 mi−2 7.1 km−2 | 2,240.695 mi2 5,803.373 km2 | 1.901 mi2 4.923 km2 | 2,242.596 mi2 5,808.296 km2 | 11,453 ft 3491 m | 4,711 ft 1436 m | 38.41° N | 108.26° W | - | - | ||
| Morgan County | 08087 | 1889-02-19 | Fort Morgan | 20 | 22.0 mi−2 8.5 km−2 | 1,280.433 mi2 3,316.305 km2 | 13.310 mi2 34.474 km2 | 1,293.743 mi2 3,350.779 km2 | 4,937 ft 1505 m | 3,989 ft 1216 m | 40.26° N | 103.81° W | - | - | ||
| Otero County | 08089 | 1889-03-25 | La Junta | 26 | 14.9 mi−2 5.8 km−2 | 1,261.961 mi2 3,268.465 km2 | 7.742 mi2 20.052 km2 | 1,269.704 mi2 3,288.518 km2 | 5,273 ft 1607 m | 3,809 ft 1161 m | 37.88° N | 103.72° W | - | - | ||
| Ouray County | 08091 | 1877-01-18 | Ouray | 52 | 8.2 mi−2 3.2 km−2 | 541.593 mi2 1,402.719 km2 | 0.618 mi2 1.600 km2 | 542.210 mi2 1,404.318 km2 | 14,158 ft 4315 m | 6,315 ft 1925 m | 38.15° N | 107.77° W | - | - | ||
| Park County | 08093 | 1861-11-01 | Fairplay | 30 | 7.4 mi−2 2.9 km−2 | 2,193.846 mi2 5,682.034 km2 | 16.807 mi2 43.531 km2 | 2,210.653 mi2 5,725.565 km2 | 14,293 ft 4357 m | 5,826 ft 1776 m | 39.12° N | 105.72° W | - | - | ||
| Phillips County | 08095 | 1889-03-27 | Holyoke | 53 | 6.5 mi−2 2.5 km−2 | 687.928 mi2 1,781.725 km2 | 0.117 mi2 0.302 km2 | 688.044 mi2 1,782.027 km2 | 4,117 ft 1255 m | 3,582 ft 1092 m | 40.59° N | 102.35° W | - | - | ||
| Pitkin County | 08097 | 1881-02-23 | Aspen | 28 | 17.7 mi−2 6.8 km−2 | 970.697 mi2 2,514.094 km2 | 2.498 mi2 6.469 km2 | 973.195 mi2 2,520.564 km2 | 14,279 ft 4352 m | 5,695 ft 1736 m | 39.22° N | 106.92° W | - | - | ||
| Prowers County | 08099 | 1889-04-11 | Lamar | 35 | 7.7 mi−2 3.0 km−2 | 1,638.394 mi2 4,243.422 km2 | 5.928 mi2 15.353 km2 | 1,644.322 mi2 4,258.775 km2 | 4,713 ft 1437 m | 3,346 ft 1020 m | 37.96° N | 102.39° W | - | - | ||
| Pueblo County | 08101 | 1861-11-01 | Pueblo | 10 | 66.7 mi−2 25.7 km−2 | 2,386.104 mi2 6,179.981 km2 | 11.691 mi2 30.280 km2 | 2,397.795 mi2 6,210.261 km2 | 12,352 ft 3765 m | 4,291 ft 1308 m | 38.17° N | 104.49° W | - | - | ||
| Rio Blanco County | 08103 | 1889-03-25 | Meeker | 44 | 2.1 mi−2 0.8 km−2 | 3,220.933 mi2 8,342.179 km2 | 1.880 mi2 4.868 km2 | 3,222.813 mi2 8,347.047 km2 | 12,033 ft 3668 m | 5,062 ft 1543 m | 39.97° N | 108.20° W | - | - | ||
| Rio Grande County | 08105 | 1874-02-10 | Del Norte | 37 | 13.1 mi−2 5.1 km−2 | 911.958 mi2 2,361.960 km2 | 0.380 mi2 0.984 km2 | 912.338 mi2 2,362.944 km2 | 13,209 ft 4026 m | 7,467 ft 2276 m | 37.49° N | 106.45° W | - | - | ||
| Routt County | 08107 | 1877-01-29 | Steamboat Springs | 23 | 10.0 mi−2 3.8 km−2 | 2,362.026 mi2 6,117.619 km2 | 6.110 mi2 15.826 km2 | 2,368.136 mi2 6,133.445 km2 | 12,185 ft 3714 m | 6,266 ft 1910 m | 40.48° N | 106.99° W | - | - | ||
| Saguache County | 08109 | 1866-12-29 | Saguache | 46 | 1.9 mi−2 0.7 km−2 | 3,168.524 mi2 8,206.441 km2 | 1.720 mi2 4.455 km2 | 3,170.244 mi2 8,210.895 km2 | 14,300 ft 4359 m | 6,013 ft 1833 m | 38.03° N | 106.25° W | - | - | ||
| San Juan County | 08111 | 1876-01-31 | Silverton | 64 | 1.8 mi−2 0.7 km−2 | 387.488 mi2 1,003.588 km2 | 0.786 mi2 2.036 km2 | 388.274 mi2 1,005.624 km2 | 13,900 ft 4237 m | 7,683 ft 2342 m | 37.78° N | 107.67° W | - | - | ||
| San Miguel County | 08113 | 1883-03-02 | Telluride | 42 | 5.7 mi−2 2.2 km−2 | 1,286.611 mi2 3,332.308 km2 | 2.013 mi2 5.214 km2 | 1,288.625 mi2 3,337.522 km2 | 14,023 ft 4274 m | 5,308 ft 1618 m | 38.01° N | 108.43° W | - | - | ||
| Sedgwick County | 08115 | 1889-04-09 | Julesburg | 57 | 4.3 mi−2 1.7 km−2 | 548.041 mi2 1,419.419 km2 | 1.363 mi2 3.531 km2 | 549.404 mi2 1,422.950 km2 | 4,127 ft 1258 m | 3,477 ft 1060 m | 40.87° N | 102.36° W | - | - | ||
| Summit County | 08117 | 1861-11-01 | Breckenridge | 19 | 46.0 mi−2 17.8 km−2 | 608.358 mi2 1,575.639 km2 | 10.920 mi2 28.283 km2 | 619.278 mi2 1,603.922 km2 | 14,278 ft 4352 m | 7,460 ft 2274 m | 39.62° N | 106.14° W | - | - | ||
| Teller County | 08119 | 1899-03-23 | Cripple Creek | 24 | 41.9 mi−2 16.2 km−2 | 557.055 mi2 1,442.767 km2 | 1.909 mi2 4.945 km2 | 558.965 mi2 1,447.712 km2 | 13,065 ft 3982 m | 5,236 ft 1596 m | 38.87° N | 105.18° W | - | - | ||
| Washington County | 08121 | 1887-02-09 | Akron | 51 | 1.9 mi−2 0.7 km−2 | 2,518.031 mi2 6,521.670 km2 | 5.872 mi2 15.207 km2 | 2,523.903 mi2 6,536.878 km2 | 5,433 ft 1656 m | 3,910 ft 1192 m | 39.97° N | 103.21° W | - | - | ||
| Weld County | 08123 | 1861-11-01 | Greeley | 9 | 63.4 mi−2 24.5 km−2 | 3,987.238 mi2 10,326.899 km2 | 29.558 mi2 76.554 km2 | 4,016.796 mi2 10,403.453 km2 | 6,388 ft 1947 m | 3,959 ft 1207 m | 40.56° N | 104.38° W | - | - | ||
| Yuma County | 08125 | 1889-03-15 | Wray | 38 | 4.2 mi−2 1.6 km−2 | 2,364.405 mi2 6,123.780 km2 | 4.299 mi2 11.135 km2 | 2,368.704 mi2 6,134.915 km2 | 4,447 ft 1355 m | 3,317 ft 1011 m | 40.00° N | 102.42° W | - | - | ||
| State of Colorado | 08 | 1876-08-01 | Denver | 48.5 mi−2 18.7 km−2 | 103,641.884 mi2 268,431.246 km2 | 451.779 mi2 1,170.101 km2 | 104,093.662 mi2 269,601.348 km2 | 14,440 ft 4401 m | 3,317 ft 1011 m | 38.99° N | 105.51° W | - | - |
County high points
Former counties
The sortable table below 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. The table includes the following information:- The official name of the county,
- The territory or state,
- The date the county was created,
- The date the county was abolished or excluded from the new Territory of Colorado, and
- Historical notes.
| County | Territory or State | Created | Superseded | History |
| Taos County | Territory of New Mexico | 1852-01-09 | 1861-02-28 | Originally one of the seven partidos of the Spanish, and later Mexican, province of Santa Fe de Nuevo México. One of the nine original counties created by the Territory of New Mexico in 1852. Excluded from the new Territory of Colorado in 1861. |
| Great Salt Lake County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created in 1852, and excluded from the new Territory of Colorado in 1861. |
| Green River County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created in 1852, but never organized. Dissolved in 1857, but recreated in 1859. Excluded from the new Territory of Colorado in 1861, and the Territory of Wyoming in 1868. Finally dissolved in 1872. |
| Iron County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created in 1852, and excluded from the new Territory of Colorado in 1861. |
| Sanpete County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created in 1852, and excluded from the new Territory of Colorado in 1861. |
| Utah County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created in 1852, and excluded from the new Territory of Colorado in 1861. |
| Washington County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created in 1852, and excluded from the new Territory of Colorado in 1861. |
| Arapahoe County | Territory of Kansas | 1855-08-25 | 1861-01-29 | Created in 1855, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Beaver County | Territory of Utah | 1856-01-05 | 1861-02-28 | Split from Iron and Millard counties in 1856. Excluded from the new Territory of Colorado in 1861. |
| Broderick County | Territory of Kansas | 1859-02-07 | 1861-01-29 | Split from Arapahoe County in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| El Paso County | Territory of Kansas | 1859-02-07 | 1861-01-29 | Split from Arapahoe County in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Fremont County | Territory of Kansas | 1859-02-07 | 1861-01-29 | Split from Arapahoe County in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Montana County | Territory of Kansas | 1859-02-07 | 1861-01-29 | Split from Arapahoe County in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Oro County | Territory of Kansas | 1859-02-07 | 1861-01-29 | Split from Arapahoe County in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Peketon County | Territory of Kansas | 1859-02-07 | 1861-01-29 | Created in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Arrappahoe County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Cheyenne County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| El Paso County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Fountain County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Heele County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Jackson County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Jefferson County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Mountain County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| North County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Park County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| St. Vrain County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Saratoga County | Territory of Jefferson | 1859-11-28 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Mora County | Territory of New Mexico | 1860-02-01 | 1861-02-28 | Split from Taos County and San Miguel County in 1860. Excluded from the new Territory of Colorado in 1861. |
| Guadalupe County | Territory of Colorado | 1861-11-01 | 1861-11-07 | One of the 17 original counties created by the Territory of Colorado in 1861. The county was renamed Conejos County after only six days. |
| Greenwood County | Territory of Colorado | 1870-02-11 | 1874-02-06 | Created from former Cheyenne and Arapaho tribal land and the eastern portion of Huerfano County in 1870. The county was abolished in 1874 and its territory split between Elbert County and Bent County. |
| Platte County | Territory of Colorado | 1872-02-09 | 1874-02-09 | Created from the eastern portion of Weld County in 1872. The county was abolished in 1874 after organizers failed to secure voter approval. The territory of the county was returned to Weld County. |
| Carbonate County | State of Colorado | 1879-02-08 | 1879-02-10 | Lake County was renamed Carbonate County in 1879. Only two days later, Carbonate County was split into the new Chaffee County and a recreated Lake County. |
| Uncompahgre County | State of Colorado | 1883-02-27 | 1883-03-02 | Ouray County was renamed Uncompahgre County for only four days in 1883. |
| South Arapahoe County | State of Colorado | 1902-11-15 | 1903-04-11 | One of three counties created from Arapahoe County in 1902. The name was changed back to Arapahoe County after five months. |
No organized counties of the District of Louisiana, the Territory of Missouri, the extralegal State of Deseret, or the Territory of Nebraska existed within the present boundaries of the state of Colorado.
County distinctions
| County | County Seat |
| Arrappahoe County | Denver City |
| Cheyenne County | |
| El Paso County | Colorado City |
| Fountain County | Pueblo |
| Heele County | La Porte |
| Jackson County | Boulder City |
| Jefferson County | Arapahoe City Golden City |
| Mountain County | Central City |
| North County | |
| Park County | Tarryall City |
| St. Vrain's County | St. Vrain |
| Saratoga County | Breckinridge |
| County | First County Seat |
| Arapahoe County | Denver City |
| Boulder County | Boulder City |
| Clear Creek County | Idaho |
| Costilla County | San Miguel |
| Douglas County | Franktown |
| El Paso County | Colorado City |
| Fremont County | Cañon City |
| Gilpin County | Central City |
| Guadaloupe County | Guadaloupe |
| Huerfano County | Autobees |
| Jefferson County | Golden City |
| Lake County | Oro City |
| Larimer County | La Porte |
| Park County | Tarryall City |
| Pueblo County | Pueblo |
| Summit County | Parkville |
| Weld County | St. Vrain |
| County | County Seat |
| Alamosa County | City of Alamosa |
| Boulder County | City of Boulder |
| City and County of Broomfield | City and County of Broomfield |
| Conejos County | unincorporated town of Conejos |
| Delta County | City of Delta |
| City and County of Denver | City and County of Denver |
| Eagle County | Town of Eagle |
| Gunnison County | City of Gunnison |
| Montrose County | City of Montrose |
| Ouray County | City of Ouray |
| Pueblo County | City of Pueblo |
| Saguache County | Town of Saguache |
| County | County Seat |
| Cheyenne County | Town of Cheyenne Wells |
| Morgan County | City of Fort Morgan |
| County | County Seat |
| Archuleta County | Town of Pagosa Springs |
| Bent County | City of Las Animas |
| City and County of Broomfield | City and County of Broomfield |
| City and County of Denver | City and County of Denver |
| Hinsdale County | Town of Lake City |
| Jackson County | Town of Walden |
| Lake County | City of Leadville |
| Mineral County | Town of Creede |
| San Juan County | Town of Silverton |
| County | County Seat | Other Counties |
| Adams County | City of Brighton | Weld County |
| Arapahoe County | City of Littleton | Douglas County and Jefferson County |
| Gilpin County | Central City | Clear Creek County |
| Rank | County | State | Mean Elevation |
| 1 | San Juan County | ||
| 2 | Hinsdale County | ||
| 3 | Lake County | ||
| 4 | Mineral County | ||
| 5 | Summit County | ||
| 6 | Clear Creek County | ||
| 7 | Pitkin County | ||
| 8 | Chaffee County | ||
| 9 | Park County | ||
| 10 | Gunnison County | ||
| 11 | Gilpin County | ||
| 12 | Grand County | ||
| 13 | Saguache County | ||
| 14 | Teller County | ||
| 15 | Rio Grande County | ||
| 16 | Custer County | ||
| 17 | Eagle County | ||
| 18 | Ouray County | ||
| 19 | Jackson County | ||
| 20 | Conejos County | ||
| 21 | Costilla County | ||
| 22 | Taos County | ||
| 23 | Summit County | ||
| 24 | Dolores County | ||
| 25 | Archuleta County |