This is a list of the 64 counties of the U.S. State of Colorado. Two counties, the City and County of Denver and the City and County of Broomfield, have consolidated city and county governments.
Colorado's postal abbreviation is CO and its FIPS state code is 08.
Contents |
|
County |
FIPS Code [1][2] |
County seat [3][4] |
Established [5] |
Formed
from [5] |
Etymolgy [5] |
Population [6] |
Area [4] |
Map |
|
|---|---|---|---|---|---|---|---|---|---|
| Adams County | 001 | Brighton | 1902-11-15 | Split from Arapahoe County. | Named in honor of Alva Adams, the 5th, 10th, and 14th Governor of the State of Colorado. | 430,836 | 1,182.29 sq mi (3,062 km 2) |
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| Alamosa County | 003 | Alamosa | 1913-03-08 | Split from Costilla County and Conejos County counties. | Named for the cottonwood trees which grow along the Rio Grande and its tributaries. Alamosa is a Spanish word for a cottonwood grove. | 15,417 | 723.21 sq mi (1,873 km 2) |
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| Arapahoe County | 005 | Littleton | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. Renamed South Arapahoe County for five months from 1902-11-15, to 1903-04-11. | Named for predecessor Arapahoe County, Kansas Territory, which in turn was named for the Arapaho Nation of Native Americans. | 554,282 | 804.41 sq mi (2,083 km 2) |
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| Archuleta County | 007 | Pagosa Springs | 1885-04-14 | Split from Conejos County. | Named in honor of Colorado State Senator Antonio D. Archuleta. | 12,648 | 1,354.53 sq mi (3,508 km 2) |
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| Baca County | 009 | Springfield | 1889-04-16 | Split from Las Animas County. | Named in honor of pioneer and Colorado territorial legislator Felipe Baca. | 3,834 | 2,558.48 sq mi (6,626 km 2) |
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| Bent County | 011 | Las Animas | 1870-02-11 | Split from Huerfano County and former Cheyenne and Arapaho tribal land. | Named in honor of frontier trader William Bent. | 5,902 | 1,541.07 sq mi (3,991 km 2) |
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| Boulder County | 013 | Boulder | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the abundance of granite boulders along Boulder Creek. | 293,161 | 740.48 sq mi (1,918 km 2) |
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| Broomfield County | 014 | Broomfield | 2001-11-15 | Split from Boulder, Adams, Jefferson, and Weld counties and reorganized as a consolidated city and county. | Named for the broom corn that was formerly grown in the area. | 54,858 | 33.57 sq mi (87 km 2) |
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| Chaffee County | 015 | Salida | 1879-02-10 | Split from Carbonate County. | Named in honor of Jerome Bunty Chaffee, one of Colorado's first two U.S. Senators from 1876 to 1879. | 16,995 | 1,014.12 sq mi (2,627 km 2) |
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| Cheyenne County | 017 | Cheyenne Wells | 1889-03-25 | Split from Elbert and Bent counties. | Named for Cheyenne Nation of Native Americans. | 1,749 | 1,781.90 sq mi (4,615 km 2) |
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| Clear Creek County | 019 | Georgetown | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for Clear Creek which runs through the county. | 8,908 | 396.53 sq mi (1,027 km 2) |
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| Conejos County | 021 | Conejos | 1861-11-01 | Guadalupe County, one of the 17 original counties of the Territory of Colorado, was renamed Conejos County after six days on 1861-11-07. | Named for the cottontail rabbits in the area. Conejos is a Spanish word for rabbits. | 8,067 | 1,290.22 sq mi (3,342 km 2) |
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| Costilla County | 023 | San Luis | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the Costilla River. Costilla is a Spanish word meaning either little rib or furring timber. | 3,232 | 1,229.38 sq mi (3,184 km 2) |
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| Crowley County | 025 | Ordway | 1911-05-29 | Split from Otero County. | Named in honor of Colorado State Senator John H. Crowley. | 6,332 | 800.27 sq mi (2,073 km 2) |
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| Custer County | 027 | Westcliffe | 1877-03-09 | Split from Fremont County. | Named in honor of George Armstrong Custer, the U.S. Army colonel defeated and killed at the Battle of Little Bighorn. | 3,999 | 739.24 sq mi (1,915 km 2) |
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| Delta County | 029 | Delta | 1883-02-11 | Split from Gunnison County. | Named for the town of Delta located at the delta of the Uncompahgre River. | 30,923 | 1,149.44 sq mi (2,977 km 2) |
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| Denver County | 031 | Denver | 1902-11-15 | The original Arapahoe County Seat was split from Arapahoe County and reorganized as a consolidated city and county. | Named in honor of James W. Denver, Governor of the Territory of Kansas from 1857 to 1859. | 598,707 | 155.66 sq mi (403 km 2) |
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| Dolores County | 033 | Dove Creek | 1881-03-04 | Split from Ouray County. | Named for the Dolores River, which was originally named el Rio de Nuestra Senora de los Dolores, which is Spanish for the River of our Lady of Sorrows. | 1,986 | 1,076.93 sq mi (2,789 km 2) |
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| Douglas County | 035 | Castle Rock | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of Stephen Arnold Douglas, U.S. Senator from Illinois from 1847 to 1861. | 280,621 | 842.30 sq mi (2,182 km 2) |
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| Eagle County | 037 | Eagle | 1883-02-11 | Split from Summit County. | Named for the Eagle River, which in turn was named for the abundance of eagles in the area. | 52,331 | 1,700.76 sq mi (4,405 km 2) |
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| Elbert County | 039 | Kiowa | 1874-02-02 | Split from Douglas County. | Named in honor of Samuel Hitt Elbert, the sixth Governor of the Territory of Colorado. | 22,929 | 1,849.08 sq mi (4,789 km 2) |
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| El Paso County | 041 | Colorado Springs | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for Ute Pass. El paso is a Spanish expression for the pass. | 596,053 | 2,128.60 sq mi (5,513 km 2) |
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| Fremont County | 043 | Cañon City | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of John Charles Frémont, the explorer, U.S. Army general, and U.S. Senator from California. | 47,283 | 1,533.09 sq mi (3,971 km 2) |
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| Garfield County | 045 | Glenwood Springs | 1883-02-10 | Split from Summit County. | Named in honor of James Abram Garfield, the twentieth President of the United States. | 55,426 | 2,958.23 sq mi (7,662 km 2) |
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| Gilpin County | 047 | Central City | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of William Gilpin, the first Governor of the Territory of Colorado. | 5,153 | 150.15 sq mi (389 km 2) |
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| Grand County | 049 | Hot Sulphur Springs | 1874-02-02 | Split from Summit County. | Named for the Grand River which was renamed the Colorado River in 1921. | 13,781 | 1,868.53 sq mi (4,839 km 2) |
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| Gunnison County | 051 | Gunnison | 1877-03-09 | Split from Lake County. | Named in honor of John Williams Gunnison, the U.S. Army captain who explored the region. | 15,147 | 3,259.22 sq mi (8,441 km 2) |
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| Hinsdale County | 053 | Lake City | 1874-02-10 | Split from Lake, Conejos, and Costilla counties. | Named in honor of George Aaron Hinsdale, a Lieutenant Governor of the Territory of Colorado. | 840 | 1,123.35 sq mi (2,909 km 2) |
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| Huerfano County | 055 | Walsenburg | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for Huerfano Butte, a solitary volcanic plug. Huerfano is a Spanish word meaning orphan. | 7,938 | 1,592.37 sq mi (4,124 km 2) |
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| Jackson County | 057 | Walden | 1909-05-05 | Split from Larimer County. | Named in honor of Andrew Jackson, the seventh President of the United States. | 1,346 | 1,619.75 sq mi (4,195 km 2) |
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| Jefferson County | 059 | Golden | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for its extralegal predecessor county, Jefferson County, Jefferson Territory, which in turn was named in honor of Thomas Jefferson, the author of the Declaration of Independence and the third President of the United States. | 533,339 | 772.85 sq mi (2,002 km 2) |
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| Kiowa County | 061 | Eads | 1889-04-11 | Split from Bent County. | Named for the Kiowa Nation of Native Americans. | 1,321 | 1,785.90 sq mi (4,625 km 2) |
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| Kit Carson County | 063 | Burlington | 1889-04-11 | Split from Elbert County. | Named in honor of Christopher Houston "Kit" Carson, the famous frontier scout and soldier. | 7,843 | 2,162.43 sq mi (5,601 km 2) |
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| Lake County | 065 | Leadville | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. Renamed Carbonate County for two days from 1879-02-08, to 1879-02-10. | Named for the Twin Lakes. | 7,994 | 383.55 sq mi (993 km 2) |
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| La Plata County | 067 | Durango | 1874-02-10 | Split from Lake and Conejos counties. | Named for the many silver deposits in the area. La plata is a Spanish expression for the silver. | 50,482 | 1,700.44 sq mi (4,404 km 2) |
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| Larimer County | 069 | Fort Collins | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of William Larimer, a pioneer entrepreneur. | 292,825 | 2,631.75 sq mi (6,816 km 2) |
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| Las Animas County | 071 | Trinidad | 1866-02-09 | Split from Huerfano County. | Named for the Animas River, which was originally named el Rio de las Animas Perdidas, which is Spanish for the River of the Souls in Purgatory. | 16,048 | 4,773.27 sq mi (12,363 km 2) |
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| Lincoln County | 073 | Hugo | 1889-04-11 | Split from Elbert and Bent counties. | Named in honor of Abraham Lincoln, the sixteenth President of the United States. | 5,286 | 2,585.21 sq mi (6,696 km 2) |
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| Logan County | 075 | Sterling | 1887-02-25 | Split from Weld County. | Named in honor of John Alexander Logan, a U.S. Army general and U.S. Senator from Illinois. | 20,905 | 1,845.31 sq mi (4,779 km 2) |
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| Mesa County | 077 | Grand Junction | 1883-02-14 | Split from Gunnison County. | Named for the mesa formations which are widespread through the area. | 143,171 | 3,345.69 sq mi (8,665 km 2) |
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| Mineral County | 079 | Creede | 1893-03-27 | Split from Hinsdale, Rio Grande, and Saguache counties. | Named from the plentiful mineral deposits found in the area. | 962 | 878.16 sq mi (2,274 km 2) |
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| Moffat County | 081 | Craig | 1911-02-27 | Split from Routt County. | Named in honor of railroad pioneer David H. Moffat. | 13,840 | 4,755.86 sq mi (12,318 km 2) |
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| Montezuma County | 083 | Cortez | 1889-04-16 | Split from La Plata County. | Named in honor of Aztec leader Moctezuma II. Ruins in the area were originally thought to have been of Aztec origin. | 25,384 | 2,035.80 sq mi (5,273 km 2) |
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| Montrose County | 085 | Montrose | 1883-02-11 | Split from Gunnison County. | Named for the town of Montrose, which in turn was probably named from the novel A Legend of Montrose, published in 1819 by Walter Scott. | 40,539 | 2,246.43 sq mi (5,818 km 2) |
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| Morgan County | 087 | Fort Morgan | 1889-02-19 | Split from Weld County. | Named for old Fort Morgan, which in turn was named in honor of U.S. Army Colonel Christopher A. Morgan. | 27,804 | 1,293.83 sq mi (3,351 km 2) |
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| Otero County | 089 | La Junta | 1889-03-25 | Split from Bent County. | Named in honor of Miguel A. Otero of the prominent Otero family of the Southwest. | 18,774 | 1,267.66 sq mi (3,283 km 2) |
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| Ouray County | 091 | Ouray | 1877-01-18 | Split from Hinsdale and Lake counties. Renamed Uncompaghre County for four days from 1883-02-27, to 1883-03-02. | Named in honor of Ouray, a Ute Native American leader. | 4,560 | 542.30 sq mi (1,405 km 2) |
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| Park County | 093 | Fairplay | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for South Park which occupies most of the county. | 16,993 | 2,209.36 sq mi (5,722 km 2) |
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| Phillips County | 095 | Holyoke | 1889-03-27 | Split from Logan County. | Named in honor of R.O. Phillips, secretary of the Lincoln Land Company. | 4,477 | 688.30 sq mi (1,783 km 2) |
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| Pitkin County | 097 | Aspen | 1881-02-23 | Split from Gunnison County. | Named in honor of Frederick Walker Pitkin, the second Governor of the State of Colorado. | 15,474 | 970.37 sq mi (2,513 km 2) |
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| Prowers County | 099 | Lamar | 1889-04-11 | Split from Bent County. | Named in honor of John W. Prowers, a pioneer of the Arkansas River valley. | 13,116 | 1,645.37 sq mi (4,261 km 2) |
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| Pueblo County | 101 | Pueblo | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for historic town of Pueblo. Pueblo is a Spanish word meaning village or people. | 156,737 | 2,396.77 sq mi (6,208 km 2) |
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| Rio Blanco County | 103 | Meeker | 1889-03-25 | Split from Garfield County. | Named for the White River, which was originally named el Rio Blanco in Spanish. | 6,340 | 3,226.24 sq mi (8,356 km 2) |
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| Rio Grande County | 105 | Del Norte | 1874-02-10 | Split from Costilla County and Conejos County counties. | Named for the Rio Grande, which flows through the area. | 11,617 | 913.10 sq mi (2,365 km 2) |
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| Routt County | 107 | Steamboat Springs | 1877-01-29 | Spilt from Grand County. | Named in honor of John Long Routt, the first Governor of the State of Colorado. | 22,980 | 2,362.11 sq mi (6,118 km 2) |
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| Saguache County | 109 | Saguache | 1866-12-29 | Split from Lake and Costilla counties. | Name comes from a Ute language word meaning "blue earth" or "water at blue earth".[7] | 7,058 | 3,168.32 sq mi (8,206 km 2) |
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| San Juan County | 111 | Silverton | 1876-01-31 | Split from Lake County. | Named for the San Juan River and San Juan Mountains, which in turn were named for Saint John the Evangelist. | 552 | 388.99 sq mi (1,007 km 2) |
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| San Miguel County | 113 | Telluride | 1883-03-02 | Split from San Juan County. | Named for the San Miguel River and San Miguel Mountains, which in turn were named for Saint Michael the Archangel. | 7,552 | 1,290.76 sq mi (3,343 km 2) |
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| Sedgwick County | 115 | Julesburg | 1889-04-09 | Split from Logan County. | Named for Fort Sedgwick, which, in turn, was named for U.S. Army General John Sedgwick. | 2,354 | 548.83 sq mi (1,421 km 2) |
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| Summit County | 117 | Breckenridge | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the many high mountain summits in the area. | 26,843 | 618.92 sq mi (1,603 km 2) |
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| Teller County | 119 | Cripple Creek | 1899-03-23 | Split from El Paso and Fremont counties. | Named in honor of Henry Moore Teller, a U.S. Senator from Colorado and United States Secretary of the Interior. | 21,661 | 558.58 sq mi (1,447 km 2) |
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| Washington County | 121 | Akron | 1887-02-09 | Split from Weld County. | Named in honor of George Washington, the first President of the United States. | 4,497 | 2,522.90 sq mi (6,534 km 2) |
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| Weld County | 123 | Greeley | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of Lewis Ledyard Weld, the first Secretary of the Territory of Colorado. | 249,775 | 4,013.84 sq mi (10,396 km 2) |
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| Yuma County | 125 | Wray | 1889-03-15 | Split from Washington County. | Named for the Yuma Native American tribe. | 9,669 | 2,369.61 sq mi (6,137 km 2) |
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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:
| County | Territory or State | Created | Superseded | History |
|---|---|---|---|---|
| Taos County | Territory of New Mexico | 1852-01-09 | 1861-02-28 | One of the seven partidos of the province of Nuevo México. One of the nine original counties created by the Territory of New Mexico in 1852. Excluded from the Territory of Colorado in 1861. |
| Great Salt Lake County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Iron County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Sanpete County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Utah County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Washington County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Green River County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Dissolved in 1857, but recreated in 1859. Excluded from the Territory of Colorado in 1861 and the Territory of Wyoming in 1868. Finally dissolved in 1872. |
| Arapahoe County | Territory of Kansas | 1855-08-25 | 1861-01-29 | Created by the Territory of Kansas 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 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 by the Territory of Kansas 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. |
| 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. |
| 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. |
| Mora County | Territory of New Mexico | 1860-02-01 | 1861-02-28 | Split from Taos County in 1860. Excluded from the 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 the renamed Lake County. |
| Uncompaghre County | State of Colorado | 1883-02-27 | 1883-03-02 | Ouray County was renamed Uncompaghre 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, or the Territory of Nebraska existed within the present boundaries of the State of Colorado.
| County | County Seat |
|---|---|
| Cheyenne County | Town of Cheyenne Wells |
| Morgan County | City of Fort Morgan |
| County | County Seat | Other Counties | |
|---|---|---|---|
| Adams County | City of Brighton | Weld County | |
| Arapahoe County | City of Littleton | Douglas County | Jefferson County |
| Gilpin County | Central City | Clear Creek County | |
|
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This is a list of the 64 counties of the U.S. State of Colorado. The counties of Colorado are important components of government since the state has no secondary civil subdivisions such as townships. Two counties, the City and County of Denver and the City and County of Broomfield, have consolidated city and county governments.
Contents |
The FIPS county code is the five-digit Federal Information Processing Standard (FIPS) code which uniquely identifies counties and county equivalents in the United States. The three-digit number is unique to each individual county within a state, but to be unique within the entire United States, it must be prefixed by the state code. This means that, for example, while Adams County, Colorado is 001, Belknap County, New Hampshire and Alachua County, Florida are also 001. To uniquely identify Adams County, Colorado, one must use the state code of 08 plus the county code of 001; therefore, the unique nationwide identifier for Adams County, Colorado is 08001. The links in the column FIPS County Code are to the Census Bureau Info page for that county.[1]
| County |
FIPS Code [1] |
County Seat [2] |
Created [3] |
Formed from [4] |
Origin of name |
Population [3][5] |
Area [6] |
Map [3] |
| Adams County | 001 | Brighton | 1902-11-15 | Split from Arapahoe County. | Named in honor of Alva Adams, the fifth Governor of the State of Colorado. | 414,338 | 3,062.12 sq mi (7,931 km²) |
File:Map of Colorado highlighting Adams County.svg |
|---|---|---|---|---|---|---|---|---|
| Alamosa County | 003 | Alamosa | 1913-03-08 | Split from Costilla County and Conejos County counties. | Named for the cottonwood trees which grow along the river and streams of the area. Alamosa is a Spanish word for a cottonwood grove. | 15,225 | 1,873.10 sq mi (4,851 km²) |
File:Map of Colorado highlighting Alamosa County.svg |
| Arapahoe County | 005 | Littleton | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. Renamed South Arapahoe County for five months from 1902-11-15, to 1903-04-11. | Named for predecessor Arapahoe County, which in turn was named for the Arapaho Native American tribe. | 537,197 | 2,083.40 sq mi (5,396 km²) |
File:Map of Colorado highlighting Arapahoe County.svg |
| Archuleta County | 007 | Pagosa Springs | 1885-04-14 | Split from Conejos County. | Named in honor of Colorado State Senator Antonio D. Archuleta. | 12,386 | 3,508.22 sq mi (9,086 km²) |
File:Map of Colorado highlighting Archuleta County.svg |
| Baca County | 009 | Springfield | 1889-04-16 | Split from Las Animas County. | Named in honor of the prominent Baca family of Trinidad, members of which had settled early in the area. | 4,017 | 6,626.43 sq mi (17,162 km²) |
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| Bent County | 011 | Las Animas | 1870-02-11 | Split from Huerfano County and former Cheyenne and Arapaho tribal land. | Named in honor of frontier trader William Bent. | 5,551 | 3,991.36 sq mi (10,338 km²) |
File:Map of Colorado highlighting Bent County.svg |
| Boulder County | 013 | Boulder | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the abundance of granite boulders in the area. | 282,304 | 1,917.83 sq mi (4,967 km²) |
File:Map of Colorado highlighting Boulder County.svg |
| Broomfield County | 014 | Broomfield | 2001-11-15 | Split from Boulder, Adams, Jefferson, and Weld counties and reorganized as a consolidated city and county. | Named for the broom corn that was formerly grown in the area. | 45,116 | 86.93 sq mi (225 km²) |
 |
| Chaffee County | 015 | Salida | 1879-02-10 | Split from Carbonate County. | Named in honor of Jerome Bunty Chaffee, a U.S. Senator from Colorado. | 16,918 | 2,626.55 sq mi (6,803 km²) |
File:Map of Colorado highlighting Chaffee County.svg |
| Cheyenne County | 017 | Cheyenne Wells | 1889-03-25 | Split from Elbert and Bent counties. | Named for the Cheyenne Native American tribe. | 1,906 | 4,615.09 sq mi (11,953 km²) |
File:Map of Colorado highlighting Cheyenne County.svg |
| Clear Creek County | 019 | Georgetown | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for Clear Creek which runs through the county. | 9,130 | 1,027.00 sq mi (2,660 km²) |
File:Map of Colorado highlighting Clear Creek County.svg |
| Conejos County | 021 | Conejos | 1861-11-01 | Guadalupe County, one of the 17 original counties of the Territory of Colorado, was renamed Conejos County after six days on 1861-11-07. | Named for the cottontail rabbits in the area. Conejos is a Spanish word for rabbits. | 8,406 | 3,341.66 sq mi (8,655 km²) |
File:Map of Colorado highlighting Conejos County.svg |
| Costilla County | 023 | San Luis | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the Costilla River. Costilla is a Spanish word meaning either little rib or furring timber. | 3,378 | 3,184.07 sq mi (8,247 km²) |
File:Map of Colorado highlighting Costilla County.svg |
| Crowley County | 025 | Ordway | 1911-05-29 | Split from Otero County. | Named in honor of Colorado State Senator John H. Crowley. | 5,386 | 2,072.68 sq mi (5,368 km²) |
File:Map of Colorado highlighting Crowley County.svg |
| Custer County | 027 | Westcliffe | 1877-03-09 | Split from Fremont County. | Named in honor of George Armstrong Custer, the U.S. Army colonel defeated at the Battle of Little Bighorn. | 3,926 | 1,914.62 sq mi (4,959 km²) |
File:Map of Colorado highlighting Custer County.svg |
| Delta County | 029 | Delta | 1883-02-11 | Split from Gunnison County. | Named for the town of Delta located at the delta of the Uncompahgre River. | 30,401 | 2,977.05 sq mi (7,711 km²) |
File:Map of Colorado highlighting Delta County.svg |
| Denver County | 031 | Denver | 1902-11-15 | The original Arapahoe County Seat was split from Arapahoe County and reorganized as a consolidated city and county. | Named in honor of James William Denver, a Governor of the Territory of Kansas. | 566,974 | 403.15 sq mi (1,044 km²) |
File:Map of Colorado highlighting Denver County.svg |
| Dolores County | 033 | Dove Creek | 1881-03-04 | Split from Ouray County. | Named for the Dolores River, which was originally named el Rio de Nuestra Senora de los Dolores, which is Spanish for the River of our Lady of Sorrows. | 1,911 | 2,789.22 sq mi (7,224 km²) |
File:Map of Colorado highlighting Dolores County.svg |
| Douglas County | 035 | Castle Rock | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of U.S. Senator Stephen Arnold Douglas of Illinois. | 263,621 | 2,181.55 sq mi (5,650 km²) |
File:Map of Colorado highlighting Douglas County.svg |
| Eagle County | 037 | Eagle | 1883-02-11 | Split from Summit County. | Named for the Eagle River, which in turn was named for the abundance of eagles in the area. | 4,985 | 4,404.94 sq mi (11,409 km²) |
File:Map of Colorado highlighting Eagle County.svg |
| El Paso County | 039 | Colorado Springs | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for Ute Pass. El paso is a Spanish exression for the pass. | 576,884 | 5,513.05 sq mi (14,279 km²) |
File:Map of Colorado highlighting El Paso County.svg |
| Elbert County | 041 | Kiowa | 1874-02-02 | Split from Douglas County. | Named in honor of Samuel Hitt Elbert, the sixth Governor of the Territory of Colorado. | 23,181 | 4,789.09 sq mi (12,404 km²) |
File:Map of Colorado highlighting Elbert County.svg |
| Fremont County | 043 | Canon City | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of John Charles Frémont, the explorer, U.S. Army general, and U.S. Senator from California. | 48,010 | 3,970.67 sq mi (10,284 km²) |
File:Map of Colorado highlighting Fremont County.svg |
| Garfield County | 045 | Glenwood Springs | 1883-02-10 | Split from Summit County. | Named in honor of James Abram Garfield, the twentieth President of the United States. | 51,908 | 7,661.78 sq mi (19,844 km²) |
File:Map of Colorado highlighting Garfield County.svg |
| Gilpin County | 047 | Central City | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of William Gilpin, the first Governor of the Territory of Colorado. | 5,042 | 388.88 sq mi (1,007 km²) |
File:Map of Colorado highlighting Gilpin County.svg |
| Grand County | 049 | Hot Sulphur Springs | 1874-02-02 | Split from Summit County. | Named for the Grand River which was renamed the Colorado River in 1921. | 13,406 | 4,839.46 sq mi (12,534 km²) |
File:Map of Colorado highlighting Grand County.svg |
| Gunnison County | 051 | Gunnison | 1877-03-09 | Split from Lake County. | Named in honor of John Williams Gunnison, the U.S. Army captain who explored the region. | 14,331 | 8,441.34 sq mi (21,863 km²) |
File:Map of Colorado highlighting Gunnison County.svg |
| Hinsdale County | 053 | Lake City | 1874-02-10 | Split from Lake, Conejos, and Costilla counties. | Named in honor of George Aaron Hinsdale, a Lieutenant Governor of the Territory of Colorado. | 819 | 2,909.47 sq mi (7,535 km²) |
File:Map of Colorado highlighting Hinsdale County.svg |
| Huerfano County | 055 | Walsenburg | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the Huerfano River. Huerfano is a Spanish word meaning orphan. | 7,808 | 4,124.22 sq mi (10,682 km²) |
File:Map of Colorado highlighting Huerfano County.svg |
| Jackson County | 057 | Walden | 1909-05-05 | Split from Larimer County. | Named in honor of Andrew Jackson, the seventh President of the United States. | 1,406 | 4,195.13 sq mi (10,865 km²) |
File:Map of Colorado highlighting Jackson County.svg |
| Jefferson County | 059 | Golden | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for its extralegal predecessor county, Jefferson County, which in turn was named in honor of Thomas Jefferson, the author of the Declaration of Independence and the third President of the United States. | 526,994 | 2,001.67 sq mi (5,184 km²) |
File:Map of Colorado highlighting Jefferson County.svg |
| Kiowa County | 061 | Eads | 1889-04-11 | Split from Bent County. | Named for the Kiowa Native American tribe. | 1,413 | 4,625.46 sq mi (11,980 km²) |
File:Map of Colorado highlighting Kiowa County.svg |
| Kit Carson County | 063 | Burlington | 1889-04-11 | Split from Elbert County. | Named in honor of Christopher Houston "Kit" Carson, the famous frontier scout and soldier. | 7,590 | 5,600.67 sq mi (14,506 km²) |
File:Map of Colorado highlighting Kit Carson County.svg |
| La Plata County | 065 | Durango | 1874-02-10 | Split from Lake and Conejos counties. | Named for the many silver deposits in the area. La plata is a Spanish expression for the silver. | 47,936 | 4,404.13 sq mi (11,407 km²) |
File:Map of Colorado highlighting La Plata County.svg |
| Lake County | 067 | Leadville | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. Renamed Carbonate County for two days from 1879-02-08, to 1879-02-10. | Named for the Twin Lakes. | 7,814 | 993.40 sq mi (2,573 km²) |
File:Map of Colorado highlighting Lake County.svg |
| Larimer County | 069 | Fort Collins | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of William Larimer, a pioneer entrepreneur. | 276,253 | 6,816.20 sq mi (17,654 km²) |
File:Map of Colorado highlighting Larimer County.svg |
| Las Animas County | 071 | Trinidad | 1866-02-09 | Split from Huerfano County. | Named for the Animas River, which was originally named el Rio de las Animas Perdidas, which is Spanish for the River of the Souls in Purgatory. | 15,564 | 12,362.71 sq mi (32,019 km²) |
File:Map of Colorado highlighting Las Animas County.svg |
| Lincoln County | 073 | Hugo | 1889-04-11 | Split from Elbert and Bent counties. | Named in honor of Abraham Lincoln, the sixteenth President of the United States. | 5,458 | 6,695.65 sq mi (17,342 km²) |
File:Map of Colorado highlighting Lincoln County.svg |
| Logan County | 075 | Sterling | 1887-02-25 | Split from Weld County. | Named in honor of John Alexander Logan, a U.S. Army general and U.S. Senator from Illinois. | 20,780 | 4,779.33 sq mi (12,378 km²) |
File:Map of Colorado highlighting Logan County.svg |
| Mesa County | 077 | Grand Junction | 1883-02-14 | Split from Gunnison County. | Named for the mesa formations which are widespread through the area. | 134,189 | 8,665.29 sq mi (22,443 km²) |
File:Map of Colorado highlighting Mesa County.svg |
| Mineral County | 079 | Creede | 1893-03-27 | Split from Hinsdale, Rio Grande, and Saguache counties. | Named from the plentiful mineral deposits found in the area. | 929 | 2,274.42 sq mi (5,891 km²) |
File:Map of Colorado highlighting Mineral County.svg |
| Moffat County | 081 | Craig | 1911-02-27 | Split from Routt County. | Named in honor of railroad pioneer David H. Moffat. | 13,680 | 12,317.62 sq mi (31,902 km²) |
File:Map of Colorado highlighting Moffat County.svg |
| Montezuma County | 083 | Cortez | 1889-04-16 | Split from La Plata County. | Named in honor of Aztec leader Moctezuma II. Ruins in the area were originally thought to have been of Aztec origin. | 25,217 | 5,272.70 sq mi (13,656 km²) |
File:Map of Colorado highlighting Montezuma County.svg |
| Montrose County | 085 | Montrose | 1883-02-11 | Split from Gunnison County. | Named for the town of Montrose, which in turn was probably named from the novel A Legend of Montrose, published in 1819 by Walter Scott. | 38,559 | 5,818.21 sq mi (15,069 km²) |
File:Map of Colorado highlighting Montrose County.svg |
| Morgan County | 087 | Fort Morgan | 1889-02-19 | Split from Weld County. | Named for old Fort Morgan, which in turn was named in honor of U.S. Army Colonel Christopher A. Morgan. | 28,109 | 3,350.99 sq mi (8,679 km²) |
File:Map of Colorado highlighting Morgan County.svg |
| Otero County | 089 | La Junta | 1889-03-25 | Split from Bent County. | Named in honor of Miguel A. Otero of the prominent Otero family of the Southwest. | 19,452 | 3,283.23 sq mi (8,504 km²) |
File:Map of Colorado highlighting Otero County.svg |
| Ouray County | 091 | Ouray | 1877-01-18 | Split from Hinsdale and Lake counties. Renamed Uncompaghre County for four days from 1883-02-27, to 1883-03-02. | Named in honor of Ouray, a Ute Native American leader. | 4,307 | 1,404.56 sq mi (3,638 km²) |
File:Map of Colorado highlighting Ouray County.svg |
| Park County | 093 | Fairplay | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for South Park which occupies most of the county. | 17,157 | 5,722.21 sq mi (14,820 km²) |
File:Map of Colorado highlighting Park County.svg |
| Phillips County | 095 | Holyoke | 1889-03-27 | Split from Logan County. | Named in honor of R.O. Phillips, secretary of the Lincoln Land Company. | 4,601 | 1,782.71 sq mi (4,617 km²) |
File:Map of Colorado highlighting Phillips County.svg |
| Pitkin County | 097 | Aspen | 1881-02-23 | Split from Gunnison County. | Named in honor of Frederick Walker Pitkin, the second Governor of the State of Colorado. | 14,798 | 2,513.24 sq mi (6,509 km²) |
File:Map of Colorado highlighting Pitkin County.svg |
| Prowers County | 099 | Lamar | 1889-04-11 | Split from Bent County. | Named in honor of John W. Prowers, a pioneer of the Arkansas River valley. | 13,776 | 4,261.49 sq mi (11,037 km²) |
File:Map of Colorado highlighting Prowers County.svg |
| Pueblo County | 101 | Pueblo | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for historic town of Pueblo. Pueblo is a Spanish word meaning village or people. | 152,912 | 6,207.60 sq mi (16,078 km²) |
File:Map of Colorado highlighting Pueblo County.svg |
| Rio Blanco County | 103 | Meeker | 1889-03-25 | Split from Garfield County. | Named for the White River, which was originally named el Rio Blanco in Spanish. | 6,180 | 8,355.91 sq mi (21,642 km²) |
File:Map of Colorado highlighting Rio Blanco County.svg |
| Rio Grande County | 105 | Del Norte | 1874-02-10 | Split from Costilla County and Conejos County counties. | Named for the Rio Grande, which flows through the area. | 12,006 | 2,364.91 sq mi (6,125 km²) |
File:Map of Colorado highlighting Rio Grande County.svg |
| Routt County | 107 | Steamboat Springs | 1877-01-29 | Spilt from Grand County. | Named in honor of John Long Routt, the first Governor of the State of Colorado. | 21,580 | 6,117.84 sq mi (15,845 km²) |
File:Map of Colorado highlighting Routt County.svg |
| Saguache County | 109 | Saguache | 1966-12-29 | Split from Lake and Costilla counties. | Name comes from a Ute language word meaning "blue earth" or "water at blue earth". | 7,006 | 8,205.91 sq mi (21,253 km²) |
File:Map of Colorado highlighting Saguache County.svg |
| San Juan County | 111 | Silverton | 1876-01-31 | Split from Lake County. | Named for the San Juan River and San Juan Mountains, which in turn were named for Saint John the Evangelist. | 578 | 1,007.48 sq mi (2,609 km²) |
File:Map of Colorado highlighting San Juan County.svg |
| San Miguel County | 113 | Telluride | 1883-03-02 | Split from San Juan County. | Named for the San Miguel River and San Miguel Mountains, which in turn were named for Saint Michael the Archangel. | 7,143 | 3,343.05 sq mi (8,658 km²) |
File:Map of Colorado highlighting San Miguel County.svg |
| Sedgwick County | 115 | Julesburg | 1889-04-09 | Split from Logan County. | Named for Fort Sedgwick, which, in turn, was named for U.S. Army General John Sedgwick. | 2,467 | 1,421.47 sq mi (3,682 km²) |
File:Map of Colorado highlighting Sedgwick County.svg |
| Summit County | 117 | Breckenridge | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named for the many high mountain summits in the area. | 25,399 | 1,602.98 sq mi (4,152 km²) |
File:Map of Colorado highlighting Summit County.svg |
| Teller County | 119 | Cripple Creek | 1899-03-23 | Split from El Paso and Fremont counties. | Named in honor of Henry Moore Teller, a U.S. Senator from Colorado and United States Secretary of the Interior. | 22,243 | 1,446.71 sq mi (3,747 km²) |
File:Map of Colorado highlighting Teller County.svg |
| Washington County | 121 | Akron | 1887-02-09 | Split from Weld County. | Named in honor of George Washington, the first President of the United States. | 4,630 | 6,534.28 sq mi (16,924 km²) |
File:Map of Colorado highlighting Washington County.svg |
| Weld County | 123 | Greeley | 1861-11-01 | Created as one of the 17 original counties of the Territory of Colorado. | Named in honor of Lewis Ledyard Weld, the first Secretary of the Territory of Colorado. | 236,857 | 10,395.79 sq mi (26,925 km²) |
File:Map of Colorado highlighting Weld County.svg |
| Yuma County | 125 | Wray | 1889-03-15 | Split from Washington County. | Named for the Yuma Native American tribe. | 9,829 | 6,137.26 sq mi (15,895 km²) |
File:Map of Colorado highlighting Yuma County.svg |
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:
| County | Territory or State | Created | Superseded | History |
|---|---|---|---|---|
| Taos County | Territory of New Mexico | 1852-01-09 | 1861-02-28 | One of the seven partidos of the province of Nuevo México. One of the nine original counties created by the Territory of New Mexico in 1852. Excluded from the Territory of Colorado in 1861. |
| Great Salt Lake County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Iron County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Sanpete County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Utah County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Washington County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Excluded from the Territory of Colorado in 1861. |
| Green River County | Territory of Utah | 1852-03-03 | 1861-02-28 | Created by the Territory of Utah in 1852. Dissolved in 1857, but recreated in 1859. Excluded from the Territory of Colorado in 1861 and the Territory of Wyoming in 1868. Finally dissolved in 1872. |
| Arapahoe County | Territory of Kansas | 1855-08-25 | 1861-01-29 | Created by the Territory of Kansas 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 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 by the Territory of Kansas in 1859, but never organized. Reverted to unorganized territory when Kansas joined the Union in 1861. |
| Arrappahoe County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Cheyenne County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| El Paso County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Fountain County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Heele County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Jackson County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Jefferson County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Montana County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| North County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Park County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| Saratoga County | Territory of Jefferson | November 1859 | 1861-02-28 | One of the 12 counties created by the extralegal Territory of Jefferson in 1859. |
| St. Vrains County | Territory of Jefferson | November 1859 | 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 in 1860. Excluded from the 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 the renamed Lake County. |
| Uncompaghre County | State of Colorado | 1883-02-27 | 1883-03-02 | Ouray County was renamed Uncompaghre 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, or the Territory of Nebraska existed within the present boundaries of the State of Colorado.
| 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 |
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| This page uses content from the English language Wikipedia. The original content was at List of counties in Colorado. The list of authors can be seen in the page history. As with this Familypedia wiki, the content of Wikipedia is available under the Creative Commons License. |
  | Colorado County Evolution by Don Stanwyck - Colorado County Evolution, Pictorial |
| | NACo - Find a county - NACo | Find a County |
| | EPA County FIPS Code Listing - EPA | Envirofacts | County FIPS Code Listing |
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