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 km^2) (Broomfield City and County) – 4,773.27 square miles (12,362.7 km^2) (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.

Table 1

County	FIPS County Code [1][2]	County seat [3][4]	Established [5]	Formed from [5]	Etymology [5]	Population [6]	Area [3]	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.	441,603	1,182.29 sq mi (3,062 km^2)
Alamosa County	003	Alamosa	1913-03-08	Split from Costilla County and Conejos County.	Named for the cottonwood trees which grow along the Rio Grande and its tributaries. Alamosa is a Spanish word for a cottonwood grove.	15,445	723.21 sq mi (1,873 km^2)
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 the five months from November 15, 1902 to April 11, 1903.	Named for predecessor Arapahoe County, Kansas Territory, which in turn was named for the Arapaho Nation of Native Americans.	572,003	804.41 sq mi (2,083 km^2)
Archuleta County	007	Pagosa Springs	1885-04-14	Split from Conejos County.	Named in honor of Colorado State Senator Antonio D. Archuleta.	12,084	1,354.53 sq mi (3,508 km^2)
Baca County	009	Springfield	1889-04-16	Split from Las Animas County.	Named in honor of pioneer and Colorado territorial legislator Felipe Baca.	3,788	2,558.48 sq mi (6,626 km^2)
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.	6,499	1,541.07 sq mi (3,991 km^2)
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.	294,567	740.48 sq mi (1,918 km^2)
City and County of Broomfield	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.	55,889	33.57 sq mi (87 km^2)
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.	17,809	1,014.12 sq mi (2,627 km^2)
Cheyenne County	017	Cheyenne Wells	1889-03-25	Split from Elbert and Bent counties.	Named for the Cheyenne Nation of Native Americans.	1,836	1,781.90 sq mi (4,615 km^2)
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 originates in the county.	9,088	396.53 sq mi (1,027 km^2)
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 November 7, 1861.	Named for the cottontail rabbits in the area. Conejos is a Spanish word for rabbits.	8,256	1,290.22 sq mi (3,342 km^2)
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.	3,524	1,229.38 sq mi (3,184 km^2)
Crowley County	025	Ordway	1911-05-29	Split from Otero County.	Named in honor of Colorado State Senator John H. Crowley.	5,823	800.27 sq mi (2,073 km^2)
Custer County	027	Westcliffe	1877-03-09	Split from Fremont County.	Named in memory of George Armstrong Custer, (1839 - 1876), the U.S. Army colonel defeated and killed at the Battle of the Little Bighorn.	4,255	739.24 sq mi (1,915 km^2)
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.	30,952	1,149.44 sq mi (2,977 km^2)
City and County of Denver	031	Denver	1902-11-15	The original Arapahoe County Seat was split from Arapahoe County and reorganized as a consolidated city and county.	Named to curry favor with James W. Denver, Governor of the Territory of Kansas from 1857 to 1859.	600,158	155.66 sq mi (403 km^2)
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.	2,064	1,076.93 sq mi (2,789 km^2)
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, (1813 - 1861), U.S. Senator from Illinois from 1847 to 1861.	285,465	842.30 sq mi (2,182 km^2)
Eagle County	037	Eagle	1883-02-11	Split from Summit County.	Named for the Eagle River which originates in the county.	52,197	1,700.76 sq mi (4,405 km^2)
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, which connects the Great Plains to South Park and was formerly located within the county. El Paso means the pass in Spanish.	622,263	2,128.60 sq mi (5,513 km^2)
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.	23,086	1,849.08 sq mi (4,789 km^2)
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 (1813 - 1890), the explorer, U.S. Army general, and U.S. Senator from California.	46,824	1,533.09 sq mi (3,971 km^2)
Garfield County	045	Glenwood Springs	1883-02-10	Split from Summit County.	Named in honor of James Abram Garfield (1831 - 1881), the twentieth President of the United States.	56,389	2,958.23 sq mi (7,662 km^2)
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.	5,441	150.15 sq mi (389 km^2)
Grand County	049	Hot Sulphur Springs	1874-02-02	Split from Summit County.	Named for the Grand River which originates in the county. The Grand River was renamed the Colorado River in 1921, but the county retains the original name.	14,843	1,868.53 sq mi (4,839 km^2)
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.	15,324	3,259.22 sq mi (8,441 km^2)
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.	843	1,123.35 sq mi (2,909 km^2)
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.	6,711	1,592.37 sq mi (4,124 km^2)
Jackson County	057	Walden	1909-05-05	Split from Larimer County.	Named in honor of Andrew Jackson (1767 - 1845), the seventh President of the United States.	1,394	1,619.75 sq mi (4,195 km^2)
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 (1743 - 1826), the author of the Declaration of Independence and the third President of the United States.	534,543	772.85 sq mi (2,002 km^2)
Kiowa County	061	Eads	1889-04-11	Split from Bent County.	Named for the Kiowa Nation of Native Americans.	1,398	1,785.90 sq mi (4,625 km^2)
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.	8,270	2,162.43 sq mi (5,601 km^2)
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.	51,334	1,700.44 sq mi (4,404 km^2)
Lake County	065	Leadville	1861-11-01	Created as one of the 17 original counties of the Territory of Colorado. Renamed Carbonate County for the two days from February 8–10, 1879.	Named for the Twin Lakes in the county.	7,310	383.55 sq mi (993 km^2)
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.	299,630	2,631.75 sq mi (6,816 km^2)
Las Animas County	071	Trinidad	1866-02-09	Split from Huerfano County.	Named for the Purgatoire River, which was originally named el Rio de las Animas Perdidas, which is Spanish for the River of the Souls in Purgatory.	15,507	4,773.27 sq mi (12,363 km^2)
Lincoln County	073	Hugo	1889-04-11	Split from Elbert and Bent counties.	Named in honor of Abraham Lincoln (1809 - 1865), the sixteenth President of the United States.	5,467	2,585.21 sq mi (6,696 km^2)
Logan County	075	Sterling	1887-02-25	Split from Weld County.	Named in honor of John Alexander Logan (1826 - 1886), a U.S. Army general and U.S. Senator from Illinois.	22,709	1,845.31 sq mi (4,779 km^2)
Mesa County	077	Grand Junction	1883-02-14	Split from Gunnison County.	Named for the mesa formations which are widespread through the area.	146,723	3,345.69 sq mi (8,665 km^2)
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.	712	878.16 sq mi (2,274 km^2)
Moffat County	081	Craig	1911-02-27	Split from Routt County.	Named in honor of railroad pioneer David H. Moffat.	13,795	4,755.86 sq mi (12,318 km^2)
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 once thought to be Aztec.	25,535	2,035.80 sq mi (5,273 km^2)
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.	41,276	2,246.43 sq mi (5,818 km^2)
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.	28,159	1,293.83 sq mi (3,351 km^2)
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.	18,831	1,267.66 sq mi (3,283 km^2)
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.	4,436	542.30 sq mi (1,405 km^2)
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.	16,206	2,209.36 sq mi (5,722 km^2)
Phillips County	095	Holyoke	1889-03-27	Split from Logan County.	Named in honor of R.O. Phillips, secretary of the Lincoln Land Company, which sold farmsteads in the area.	4,442	688.30 sq mi (1,783 km^2)
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.	17,148	970.37 sq mi (2,513 km^2)
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.	12,551	1,645.37 sq mi (4,261 km^2)
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.	159,063	2,396.77 sq mi (6,208 km^2)
Rio Blanco County	103	Meeker	1889-03-25	Split from Garfield County.	Named for the White River, which was originally named Rio Blanco in Spanish.	6,666	3,226.24 sq mi (8,356 km^2)
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.	11,982	913.10 sq mi (2,365 km^2)
Routt County	107	Steamboat Springs	1877-01-29	Split from Grand County.	Named in honor of John Long Routt, the first Governor of the State of Colorado.	23,509	2,362.11 sq mi (6,118 km^2)
Saguache County	109	Saguache	1866-12-29	Split from Lake and Costilla counties.	Name comes from a Ute language noun meaning "sand dunes".[7][8]	6,108	3,168.32 sq mi (8,206 km^2)
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.	699	388.99 sq mi (1,007 km^2)
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.	7,359	1,290.76 sq mi (3,343 km^2)
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 (1813 - 1864).	2,379	548.83 sq mi (1,421 km^2)
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.	27,994	618.92 sq mi (1,603 km^2)
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.	23,350	558.58 sq mi (1,447 km^2)
Washington County	121	Akron	1887-02-09	Split from Weld County.	Named in honor of George Washington (1732 - 1799), the first President of the United States.	4,814	2,522.90 sq mi (6,534 km^2)
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.	252,825	4,013.84 sq mi (10,396 km^2)
Yuma County	125	Wray	1889-03-15	Split from Washington County.	Named for the Quechan (Yuma) Nation of Native Americans.	10,043	2,369.61 sq mi (6,137 km^2)

Table 2

An enlargeable map of the 64 counties of the state of Colorado

The following sortable table lists the 64 counties of the state of Colorado with the following information:

1. The official name of the county,^[9]
2. The International Committee for Information Technology Standards (INCITS) county code.^[10]
3. The date the county was established,^[11]
4. The county seat,^[12]
5. The rank among the 64 counties of Colorado by population as of July 1, 2013, as estimated by the United States Census Bureau,^[10]
6. The county population as of July 1, 2013, as estimated by the United States Census Bureau,^[10]
7. The county population as of April 1, 2010, as enumerated by the 2010 United States Census,^[10]
8. The percent population change from April 1, 2010, to July 1, 2013,^[10]
9. A link to a detailed transportation map of the county.^[13]
10. The average population density per land area of the county as of July 1, 2012,^[10]
11. The land area of the county,^[10]
12. The water area of the county,^[10]
13. The total area of the county,^[10]
14. The maximum surface elevation in the county,^[14][15][16]
15. The minimum surface elevation in the county,^[16][17][18]
16. The reference latitude of the county,^[10] and
17. The reference longitude of the county.^[10]

The 64 Counties of the State of Colorado

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	469,193	441,603	+6.25%	map	393.6 mi^−2 152.0 km^−2	1,167.653 mi^2 3,024.208 km^2	16.243 mi^2 42.070 km^2	1,183.897 mi^2 3,066.278 km^2	5,668 ft 1728 m	4,432 ft 1351 m	39.87° N	104.33° W
Alamosa County	08003	1913-03-08	Alamosa	29	16,253	15,445	+5.23%	map	21.4 mi^−2 8.3 km^−2	722.643 mi^2 1,871.637 km^2	0.698 mi^2 1.808 km^2	723.341 mi^2 1,873.445 km^2	14,351 ft 4374 m	6,387 ft 1947 m	37.57° N	105.79° W
Arapahoe County	08005	1861-11-01	Littleton	3	607,070	572,003	+6.13%	map	716.7 mi^−2 276.7 km^−2	798.100 mi^2 2,067.070 km^2	7.337 mi^2 19.004 km^2	805.438 mi^2 2,086.074 km^2	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	12,194	12,084	+0.91%	map	8.9 mi^−2 3.5 km^−2	1,350.175 mi^2 3,496.938 km^2	5.339 mi^2 13.828 km^2	1,355.514 mi^2 3,510.765 km^2	13,308 ft 4056 m	6,085 ft 1855 m	37.20° N	107.05° W
Baca County	08009	1889-04-16	Springfield	55	3,682	3,788	−2.80%	map	1.5 mi^−2 0.6 km^−2	2,554.967 mi^2 6,617.334 km^2	2.372 mi^2 6.142 km^2	2,557.338 mi^2 6,623.476 km^2	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	5,688	6,499	−12.48%	map	4.3 mi^−2 1.7 km^−2	1,512.861 mi^2 3,918.292 km^2	28.222 mi^2 73.094 km^2	1,541.083 mi^2 3,991.386 km^2	4,857 ft 1481 m	3,671 ft 1119 m	37.93° N	103.08° W
Boulder County	08013	1861-11-01	Boulder	7	310,048	294,567	+5.26%	map	405.6 mi^−2 156.6 km^−2	726.289 mi^2 1,881.080 km^2	14.081 mi^2 36.469 km^2	740.370 mi^2 1,917.549 km^2	14,259 ft 4346 m	4,717 ft 1438 m	40.09° N	105.40° W
BroCity and County of Broomfield	08014	2001-11-15	Broomfield	12	59,471	55,889	+6.41%	map	1,691.9 mi^−2 653.2 km^−2	33.034 mi^2 85.558 km^2	0.566 mi^2 1.466 km^2	33.600 mi^2 87.024 km^2	5,848 ft 1783 m	4,691 ft 1430 m	39.95° N	105.05° W
Chaffee County	08015	1879-02-10	Salida	27	18,510	17,809	+3.94%	map	17.6 mi^−2 6.8 km^−2	1,013.403 mi^2 2,624.702 km^2	1.550 mi^2 4.013 km^2	1,014.953 mi^2 2,628.716 km^2	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	1,890	1,836	+2.94%	map	1.0 mi^−2 0.4 km^−2	1,778.276 mi^2 4,605.713 km^2	3.153 mi^2 8.166 km^2	1,781.429 mi^2 4,613.879 km^2	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	9,031	9,088	−0.63%	map	23.0 mi^−2 8.9 km^−2	395.227 mi^2 1,023.633 km^2	1.266 mi^2 3.280 km^2	396.493 mi^2 1,026.913 km^2	14,278 ft 4352 m	5,075 ft 1547 m	39.69° N	105.67° W
Conejos County	08021	1861-11-07	Conejos	40	8,277	8,256	+0.25%	map	6.4 mi^−2 2.5 km^−2	1,287.391 mi^2 3,334.326 km^2	3.566 mi^2 9.235 km^2	1,290.956 mi^2 3,343.561 km^2	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	3,518	3,524	−0.17%	map	2.9 mi^−2 1.1 km^−2	1,226.952 mi^2 3,177.790 km^2	3.409 mi^2 8.829 km^2	1,230.360 mi^2 3,186.619 km^2	14,351 ft 4374 m	7,375 ft 2248 m	37.28° N	105.43° W
Crowley County	08025	1911-05-29	Ordway	50	5,322	5,823	−8.60%	map	7.4 mi^−2 2.9 km^−2	787.421 mi^2 2,039.411 km^2	12.908 mi^2 33.430 km^2	800.329 mi^2 2,072.842 km^2	5,228 ft 1593 m	3,966 ft 1209 m	38.32° N	103.79° W
Custer County	08027	1877-03-09	Westcliffe	54	4,285	4,255	+0.71%	map	5.8 mi^−2 2.2 km^−2	738.625 mi^2 1,913.031 km^2	1.299 mi^2 3.365 km^2	739.925 mi^2 1,916.396 km^2	14,246 ft 4342 m	4,547 ft 1386 m	38.10° N	105.37° W
Delta County	08029	1883-02-11	Delta	18	30,483	30,952	−1.52%	map	27.1 mi^−2 10.5 km^−2	1,142.050 mi^2 2,957.897 km^2	6.549 mi^2 16.961 km^2	1,148.599 mi^2 2,974.858 km^2	11,396 ft 3474 m	4,763 ft 1452 m	38.86° N	107.86° W
DenCity and County of Denver	08031	1902-11-15	Denver	2	649,495	600,158	+8.22%	map	3,922.6 mi^−2 1,514.5 km^−2	153.000 mi^2 396.269 km^2	1.631 mi^2 4.225 km^2	154.632 mi^2 400.494 km^2	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	2,029	2,064	−1.70%	map	1.9 mi^−2 0.7 km^−2	1,067.051 mi^2 2,763.650 km^2	1.049 mi^2 2.716 km^2	1,068.100 mi^2 2,766.366 km^2	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	305,963	285,465	+7.18%	map	339.7 mi^−2 131.2 km^−2	840.248 mi^2 2,176.232 km^2	2.621 mi^2 6.789 km^2	842.869 mi^2 2,183.022 km^2	9,836 ft 2998 m	5,242 ft 1598 m	39.33° N	104.93° W
Eagle County	08037	1883-02-11	Eagle	15	52,460	52,197	+0.50%	map	31.0 mi^−2 12.0 km^−2	1,684.530 mi^2 4,362.912 km^2	7.261 mi^2 18.806 km^2	1,691.791 mi^2 4,381.718 km^2	14,011 ft 4271 m	6,220 ft 1896 m	39.63° N	106.69° W
Elbert County	08039	1874-02-02	Kiowa	22	23,733	23,086	+2.80%	map	12.5 mi^−2 4.8 km^−2	1,850.847 mi^2 4,793.671 km^2	0.171 mi^2 0.442 km^2	1,851.018 mi^2 4,794.113 km^2	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	655,044	622,263	+5.27%	map	292.6 mi^−2 113.0 km^−2	2,126.801 mi^2 5,508.390 km^2	2.746 mi^2 7.112 km^2	2,129.547 mi^2 5,515.501 km^2	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	46,451	46,824	−0.80%	map	30.5 mi^−2 11.8 km^−2	1,533.068 mi^2 3,970.627 km^2	0.863 mi^2 2.235 km^2	1,533.931 mi^2 3,972.863 km^2	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	57,302	56,389	+1.62%	map	19.1 mi^−2 7.4 km^−2	2,947.563 mi^2 7,634.154 km^2	8.274 mi^2 21.431 km^2	2,955.838 mi^2 7,655.584 km^2	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	5,601	5,441	+2.94%	map	36.3 mi^−2 14.0 km^−2	149.896 mi^2 388.229 km^2	0.364 mi^2 0.942 km^2	150.260 mi^2 389.171 km^2	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	14,289	14,843	−3.73%	map	8.0 mi^−2 3.1 km^−2	1,846.330 mi^2 4,781.972 km^2	23.263 mi^2 60.250 km^2	1,869.592 mi^2 4,842.222 km^2	13,559 ft 4133 m	6,040 ft 1841 m	40.12° N	106.10° W
Gunnison County	08051	1877-03-09	Gunnison	31	15,507	15,324	+1.19%	map	4.7 mi^−2 1.8 km^−2	3,239.099 mi^2 8,389.229 km^2	20.530 mi^2 53.172 km^2	3,259.629 mi^2 8,442.401 km^2	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	813	843	−3.56%	map	0.8 mi^−2 0.3 km^−2	1,117.251 mi^2 2,893.668 km^2	5.917 mi^2 15.325 km^2	1,123.168 mi^2 2,908.992 km^2	14,321 ft 4365 m	7,299 ft 2225 m	37.81° N	107.38° W
Huerfano County	08055	1861-11-01	Walsenburg	45	6,519	6,711	−2.86%	map	4.2 mi^−2 1.6 km^−2	1,591.001 mi^2 4,120.673 km^2	2.236 mi^2 5.792 km^2	1,593.237 mi^2 4,126.465 km^2	14,326 ft 4366 m	4,445 ft 1355 m	37.69° N	104.96° W
Jackson County	08057	1909-05-05	Walden	61	1,365	1,394	−2.08%	map	0.9 mi^−2 0.3 km^−2	1,613.723 mi^2 4,179.523 km^2	7.239 mi^2 18.750 km^2	1,620.962 mi^2 4,198.273 km^2	12,954 ft 3948 m	4,865 ft 1483 m	40.66° N	106.33° W
Jefferson County	08059	1861-11-01	Golden	4	551,798	534,543	+3.23%	map	699.5 mi^−2 270.1 km^−2	764.208 mi^2 1,979.290 km^2	9.825 mi^2 25.446 km^2	774.033 mi^2 2,004.736 km^2	11,589 ft 3532 m	4,986 ft 1520 m	39.59° N	105.25° W
Kiowa County	08061	1889-04-11	Eads	60	1,423	1,398	+1.79%	map	0.8 mi^−2 0.3 km^−2	1,767.767 mi^2 4,578.496 km^2	18.160 mi^2 47.033 km^2	1,785.927 mi^2 4,625.529 km^2	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	8,037	8,270	−2.82%	map	3.8 mi^−2 1.5 km^−2	2,160.822 mi^2 5,596.502 km^2	0.869 mi^2 2.252 km^2	2,161.691 mi^2 5,598.754 km^2	5,297 ft 1615 m	3,523 ft 1074 m	39.31° N	102.60° W
Lake County	08065	1861-11-01	Leadville	43	7,306	7,310	−0.05%	map	19.4 mi^−2 7.5 km^−2	376.911 mi^2 976.194 km^2	6.998 mi^2 18.124 km^2	383.909 mi^2 994.319 km^2	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	53,284	51,334	+3.80%	map	30.3 mi^−2 11.7 km^−2	1,692.078 mi^2 4,382.463 km^2	7.629 mi^2 19.760 km^2	1,699.708 mi^2 4,402.223 km^2	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	315,988	299,630	+5.46%	map	115.4 mi^−2 44.6 km^−2	2,596.002 mi^2 6,723.613 km^2	37.952 mi^2 98.295 km^2	2,633.954 mi^2 6,821.909 km^2	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	14,446	15,507	−6.84%	map	3.2 mi^−2 1.3 km^−2	4,772.671 mi^2 12,361.162 km^2	2.676 mi^2 6.930 km^2	4,775.347 mi^2 12,368.092 km^2	13,631 ft 4155 m	4,317 ft 1316 m	37.32° N	104.04° W
Lincoln County	08073	1889-04-11	Hugo	49	5,430	5,467	−0.68%	map	2.1 mi^−2 0.8 km^−2	2,577.626 mi^2 6,676.021 km^2	8.796 mi^2 22.781 km^2	2,586.422 mi^2 6,698.802 km^2	5,973 ft 1821 m	3,923 ft 1196 m	38.99° N	103.51° W
Logan County	08075	1887-02-25	Sterling	25	22,450	22,709	−1.14%	map	12.4 mi^−2 4.8 km^−2	1,838.546 mi^2 4,761.813 km^2	6.318 mi^2 16.364 km^2	1,844.864 mi^2 4,778.177 km^2	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	147,554	146,723	+0.57%	map	44.1 mi^−2 17.0 km^−2	3,328.974 mi^2 8,622.003 km^2	12.149 mi^2 31.467 km^2	3,341.123 mi^2 8,653.470 km^2	11,236 ft 3425 m	4,337 ft 1322 m	39.02° N	108.46° W
Mineral County	08079	1893-03-27	Creede	63	721	712	+1.26%	map	0.8 mi^−2 0.3 km^−2	875.666 mi^2 2,267.966 km^2	2.016 mi^2 5.222 km^2	877.683 mi^2 2,273.188 km^2	13,902 ft 4237 m	7,549 ft 2301 m	37.65° N	106.93° W
Moffat County	08081	1911-02-27	Craig	34	13,103	13,795	−5.02%	map	2.9 mi^−2 1.1 km^−2	4,743.290 mi^2 12,285.065 km^2	7.622 mi^2 19.742 km^2	4,750.912 mi^2 12,304.807 km^2	10,840 ft 3304 m	4,993 ft 1522 m	40.57° N	108.20° W
Montezuma County	08083	1889-04-16	Cortez	21	25,642	25,535	+0.42%	map	12.6 mi^−2 4.9 km^−2	2,029.527 mi^2 5,256.451 km^2	10.624 mi^2 27.517 km^2	2,040.151 mi^2 5,283.968 km^2	13,237 ft 4035 m	4,639 ft 1414 m	37.34° N	108.60° W
Montrose County	08085	1883-02-11	Montrose	17	40,713	41,276	−1.36%	map	18.4 mi^−2 7.1 km^−2	2,240.695 mi^2 5,803.373 km^2	1.901 mi^2 4.923 km^2	2,242.596 mi^2 5,808.296 km^2	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	28,404	28,159	+0.87%	map	22.0 mi^−2 8.5 km^−2	1,280.433 mi^2 3,316.305 km^2	13.310 mi^2 34.474 km^2	1,293.743 mi^2 3,350.779 km^2	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	18,703	18,831	−0.68%	map	14.9 mi^−2 5.8 km^−2	1,261.961 mi^2 3,268.465 km^2	7.742 mi^2 20.052 km^2	1,269.704 mi^2 3,288.518 km^2	5,273 ft 1607 m	3,809 ft 1161 m	37.88° N	103.72° W
Ouray County	08091	1877-01-18	Ouray	52	4,557	4,436	+2.73%	map	8.2 mi^−2 3.2 km^−2	541.593 mi^2 1,402.719 km^2	0.618 mi^2 1.600 km^2	542.210 mi^2 1,404.318 km^2	14,158 ft 4315 m	6,315 ft 1925 m	38.15° N	107.77° W
Park County	08093	1861-11-01	Fairplay	30	16,121	16,206	−0.52%	map	7.4 mi^−2 2.9 km^−2	2,193.846 mi^2 5,682.034 km^2	16.807 mi^2 43.531 km^2	2,210.653 mi^2 5,725.565 km^2	14,293 ft 4357 m	5,826 ft 1776 m	39.12° N	105.72° W
Phillips County	08095	1889-03-27	Holyoke	53	4,356	4,442	−1.94%	map	6.5 mi^−2 2.5 km^−2	687.928 mi^2 1,781.725 km^2	0.117 mi^2 0.302 km^2	688.044 mi^2 1,782.027 km^2	4,117 ft 1255 m	3,582 ft 1092 m	40.59° N	102.35° W
Pitkin County	08097	1881-02-23	Aspen	28	17,379	17,148	+1.35%	map	17.7 mi^−2 6.8 km^−2	970.697 mi^2 2,514.094 km^2	2.498 mi^2 6.469 km^2	973.195 mi^2 2,520.564 km^2	14,279 ft 4352 m	5,695 ft 1736 m	39.22° N	106.92° W
Prowers County	08099	1889-04-11	Lamar	35	12,291	12,551	−2.07%	map	7.7 mi^−2 3.0 km^−2	1,638.394 mi^2 4,243.422 km^2	5.928 mi^2 15.353 km^2	1,644.322 mi^2 4,258.775 km^2	4,713 ft 1437 m	3,346 ft 1020 m	37.96° N	102.39° W
Pueblo County	08101	1861-11-01	Pueblo	10	161,451	159,063	+1.50%	map	66.7 mi^−2 25.7 km^−2	2,386.104 mi^2 6,179.981 km^2	11.691 mi^2 30.280 km^2	2,397.795 mi^2 6,210.261 km^2	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	6,807	6,666	+2.12%	map	2.1 mi^−2 0.8 km^−2	3,220.933 mi^2 8,342.179 km^2	1.880 mi^2 4.868 km^2	3,222.813 mi^2 8,347.047 km^2	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	11,803	11,982	−1.49%	map	13.1 mi^−2 5.1 km^−2	911.958 mi^2 2,361.960 km^2	0.380 mi^2 0.984 km^2	912.338 mi^2 2,362.944 km^2	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	23,513	23,509	+0.02%	map	10.0 mi^−2 3.8 km^−2	2,362.026 mi^2 6,117.619 km^2	6.110 mi^2 15.826 km^2	2,368.136 mi^2 6,133.445 km^2	12,185 ft 3714 m	6,266 ft 1910 m	40.48° N	106.99° W
Saguache County[7][8]	08109	1866-12-29	Saguache	46	6,208	6,108	+1.64%	map	1.9 mi^−2 0.7 km^−2	3,168.524 mi^2 8,206.441 km^2	1.720 mi^2 4.455 km^2	3,170.244 mi^2 8,210.895 km^2	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	692	699	−1.00%	map	1.8 mi^−2 0.7 km^−2	387.488 mi^2 1,003.588 km^2	0.786 mi^2 2.036 km^2	388.274 mi^2 1,005.624 km^2	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	7,678	7,359	+4.33%	map	5.7 mi^−2 2.2 km^−2	1,286.611 mi^2 3,332.308 km^2	2.013 mi^2 5.214 km^2	1,288.625 mi^2 3,337.522 km^2	14,023 ft 4274 m	5,308 ft 1618 m	38.01° N	108.43° W
Sedgwick County	08115	1889-04-09	Julesburg	57	2,360	2,379	−0.80%	map	4.3 mi^−2 1.7 km^−2	548.041 mi^2 1,419.419 km^2	1.363 mi^2 3.531 km^2	549.404 mi^2 1,422.950 km^2	4,127 ft 1258 m	3,477 ft 1060 m	40.87° N	102.36° W
Summit County	08117	1861-11-01	Breckenridge	19	28,649	27,994	+2.34%	map	46.0 mi^−2 17.8 km^−2	608.358 mi^2 1,575.639 km^2	10.920 mi^2 28.283 km^2	619.278 mi^2 1,603.922 km^2	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	23,275	23,350	−0.32%	map	41.9 mi^−2 16.2 km^−2	557.055 mi^2 1,442.767 km^2	1.909 mi^2 4.945 km^2	558.965 mi^2 1,447.712 km^2	13,065 ft 3982 m	5,236 ft 1596 m	38.87° N	105.18° W
Washington County	08121	1887-02-09	Akron	51	4,803	4,814	−0.23%	map	1.9 mi^−2 0.7 km^−2	2,518.031 mi^2 6,521.670 km^2	5.872 mi^2 15.207 km^2	2,523.903 mi^2 6,536.878 km^2	5,433 ft 1656 m	3,910 ft 1192 m	39.97° N	103.21° W
Weld County	08123	1861-11-01	Greeley	9	269,785	252,825	+6.71%	map	63.4 mi^−2 24.5 km^−2	3,987.238 mi^2 10,326.899 km^2	29.558 mi^2 76.554 km^2	4,016.796 mi^2 10,403.453 km^2	6,388 ft 1947 m	3,959 ft 1207 m	40.56° N	104.38° W
Yuma County	08125	1889-03-15	Wray	38	10,151	10,043	+1.08%	map	4.2 mi^−2 1.6 km^−2	2,364.405 mi^2 6,123.780 km^2	4.299 mi^2 11.135 km^2	2,368.704 mi^2 6,134.915 km^2	4,447 ft 1355 m	3,317 ft 1011 m	40.00° N	102.42° W
State of Colorado	08	1876-08-01	Denver		5,268,367	5,029,196	+4.76%	map	48.5 mi^−2 18.7 km^−2	103,641.884 mi^2 268,431.246 km^2	451.779 mi^2 1,170.101 km^2	104,093.662 mi^2 269,601.348 km^2	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^[19] 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:

1. The official name of the county,
2. The territory or state,
3. The date the county was created,
4. The date the county was abolished or excluded from the new Territory of Colorado, and
5. Historical notes.

Counties formerly within the area of the State of Colorado

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.
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, the extralegal State of Deseret, or the Territory of Nebraska existed within the present boundaries of the state of Colorado.

County distinctions

1. Costilla County was the first area within the present State of Colorado to be settled by Europeans in 1851.

2. Taos County, created by the Territory of New Mexico in 1852, was the first organized county to extend into the area of the present State of Colorado.

3. Arapahoe County, created by the Territory of Kansas in 1855, was the first county created exclusively within the area of the present State of Colorado.

4. On November 28, 1859, the extralegal Territory of Jefferson created 12 counties:^[19]

The 12 counties of the
Territory of Jefferson

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

5. On November 1, 1861, the Territory of Colorado created the 17 original Colorado counties:^[11]

The 17 original counties of the
Territory of Colorado

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

6. Of the 17 original Colorado counties created in 1861, only Gilpin County and Clear Creek County have retained their original boundaries with only minor survey changes.

7. Guadalupe County was the first Colorado county to be renamed in 1861.

8. Las Animas County was the first new Colorado county to be created (in 1866) after the original 17 counties.

9. Greenwood County was the longest lived former Colorado county, existing four years from 1870 to 1874.

10. In 1876, San Juan County became the last county created by the Territory of Colorado.

11. In 1877, Ouray County became the first county created by the new State of Colorado.

12. Carbonate County was the shortest lived former Colorado county, existing only two days in 1879 before being dissolved.

13. The City and County of Broomfield became the newest Colorado county in 2001.

14. Las Animas County is the most extensive Colorado county.

15. The City and County of Broomfield is the least extensive Colorado county.

16. El Paso County is the most populous Colorado county.

17. San Juan County is the least populous Colorado county.

18. El Paso County and the City and County of Denver are among the 100 most populous counties of the United States.

19. San Juan County, Mineral County, Hinsdale County, Jackson County, Kiowa County, Cheyenne County, and Dolores County are among the 100 least populous counties of the United States.

20. The City and County of Denver is the most densely populated Colorado county.

21. Hinsdale County is the least densely populated Colorado county.

22. Hinsdale County, Kiowa County, Mineral County, and Jackson County have fewer than one resident per square mile (0.386 km⁻²).

23. Lake County has the highest point in Colorado at the summit of Mount Elbert at 14,440 feet (4,401 m) elevation (the highest point in the entire Rocky Mountains).

24. Yuma County has the lowest point in Colorado where the Arikaree River flows into Kansas at 3,317 feet (1,011 m) elevation (the highest low point of any U.S. state).

25. Jefferson County borders ten other counties, the most of any Colorado county.^[20]

26. Delta County and the City and County of Denver each border only three other counties, the fewest of Colorado counties.^[21]

27. The following twelve Colorado counties have a county seat with the same name as the county:

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

28. The name of each of the following two Colorado counties forms one part of the name of its county seat:

County	County Seat
Cheyenne County	Town of Cheyenne Wells
Morgan County	City of Fort Morgan

29. Weld County has the most incorporated municipalities of any Colorado county with 31.

30. The following nine Colorado counties have no incorporated municipalities other than their county seat:

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

31. Of all 64 Colorado counties, only Conejos County has a county seat that is not an incorporated municipality.

32. Only three Colorado county seats extend into other counties:

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

33. The City and County of Denver and the City and County of Broomfield are the only two Colorado counties with enclaves.

34. Arapahoe County, Boulder County, and Jefferson County are the only three dismembered Colorado counties with exclaves.

35. San Juan County has the highest mean elevation of any U.S. county at 11,240 feet (3,426 m). The 25 highest U.S. counties by mean elevation are:^[22]

Highest Counties in the United States

Rank	County	State	Mean Elevation
1	San Juan County	Colorado	11,240 feet (3,426 m)
2	Hinsdale County	Colorado	10,826 feet (3,300 m)
3	Lake County	Colorado	10,790 feet (3,289 m)
4	Mineral County	Colorado	10,411 feet (3,173 m)
5	Summit County	Colorado	10,365 feet (3,159 m)
6	Clear Creek County	Colorado	10,264 feet (3,128 m)
7	Pitkin County	Colorado	9,940 feet (3,030 m)
8	Chaffee County	Colorado	9,915 feet (3,022 m)
9	Park County	Colorado	9,572 feet (2,918 m)
10	Gunnison County	Colorado	9,488 feet (2,892 m)
11	Gilpin County	Colorado	9,236 feet (2,815 m)
12	Grand County	Colorado	9,204 feet (2,805 m)
13	Saguache County	Colorado	9,193 feet (2,802 m)
14	Teller County	Colorado	9,052 feet (2,759 m)
15	Rio Grande County	Colorado	9,011 feet (2,747 m)
16	Custer County	Colorado	8,988 feet (2,740 m)
17	Eagle County	Colorado	8,987 feet (2,739 m)
18	Ouray County	Colorado	8,951 feet (2,728 m)
19	Jackson County	Colorado	8,863 feet (2,701 m)
20	Conejos County	Colorado	8,774 feet (2,674 m)
21	Costilla County	Colorado	8,681 feet (2,646 m)
22	Taos County	New Mexico	8,510 feet (2,594 m)
23	Summit County	Utah	8,388 feet (2,557 m)
24	Dolores County	Colorado	8,280 feet (2,524 m)
25	Archuleta County	Colorado	8,101 feet (2,469 m)

See also

• State of Colorado
  • Colorado census designated places
  • Colorado census statistical areas
    • Colorado counties ranked by per capita income
    • List of counties in Colorado
    • Wikimedia Commons: Counties in Colorado
  • Colorado metropolitan areas
  • Colorado municipalities
    • List of city nicknames in Colorado
    • Table of Colorado municipalities by county
    • Wikimedia Commons: Cities in Colorado
  • Geography of Colorado
  • History of Colorado
  • List of cities and towns in Colorado
    • Colorado places ranked by per capita income
  • List of forts in Colorado
  • List of ghost towns in Colorado
  • List of places in Colorado
  • Outline of Colorado
    • Index of Colorado-related articles
  • Wikimedia Commons: Colorado
• United States Census Bureau
  • 2010 United States Census

References

1. "EPA County FIPS Code Listing". EPA.gov. Retrieved 2008-02-23.
2. The ANSI INCITS 31:2009 county code is the five-digit 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 two-digit ANSI INCITS 31:2009 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 INCITS are to the Census Bureau Info page for that county.
3. National Association of Counties. "NACo - Find a county". Archived from the original on September 27, 2007. Retrieved 2008-04-30.
4. "Colorado County Seats". State of Colorado, Department of Public Health and Environment. 2007-01-30. Retrieved 2007-01-30.
5. "Colorado Government History". State of Colorado, Department of Personnel & Administration, Colorado State Archives. 2001-04-18. Retrieved 2008-09-25.
6. "2010 United States Census website". United States Census Bureau, Population Division. Retrieved April 22, 2011.
7. The name "Saguache" is pronounced /səˈwætʃ/. This name comes from the Ute language noun "sawup" /səˈwʌp/ meaning "sand dunes". The Spanish language version of this name is usually spelled "Saguache", while the English language version is usually spelled "Sawatch".
8. Merkl, Dameon (February 26, 2013), "What's in a Colorado name pronunciation?", The Denver Post, retrieved March 7, 2013
9. "Colorado Counties as of May 1, 2011". State of Colorado, Department of Local Affairs. May 1, 2011. Retrieved May 2, 2011.
10. "Annual Estimates of the Resident Population for Counties: April 1, 2010 to July 1, 2013". 2013 Population Estimates. United States Census Bureau, Population Division. March 2014. Retrieved April 18, 2014.
11. "Colorado Government History". State of Colorado, Department of Personnel & Administration, Colorado State Archives. April 18, 2001. Retrieved May 2, 2011.
12. "Colorado County Seats". State of Colorado, Department of Public Health and Environment. Retrieved May 2, 2011.
13. "Colorado Department of Transportation Maps". State of Colorado, Department of Transportation. Retrieved May 6, 2011.
14. See the Table of the highest major summits of Colorado
15. "Colorado County High Points". peakbagger.com. Retrieved May 2, 2011. External link in |publisher= (help)
16. Elevations include an adjustment from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). For further information, please see this United States National Geodetic Survey note.
17. "Colorado County Maps". anyplaceamerica.com. Retrieved May 2, 2011. External link in |publisher= (help)
18. Only a few of these county low points have been verified.
19. Provisional Laws and Joint Resolutions of the General Assembly of Jefferson Territory. General Assembly of the Territory of Jefferson. 1859–1860. Retrieved 2011-05-05.
20. Jefferson County, Colorado, borders Boulder County, the City and County of Broomfield, Adams County, the City and County of Denver, Arapahoe County, Douglas County, Teller County, Park County, Clear Creek County, and Gilpin County, Colorado.
21. Delta County, Colorado, borders Gunnison County, Montrose County, and Mesa County, Colorado. The City and County of Denver, Colorado, borders Adams County, Arapahoe County, and Jefferson County, Colorado.
22. "Mean County Elevation Lists". County Highpointers. Retrieved May 2, 2011.

External links

• Colorado County Evolution by Don Stanwyck
• Colorado Historical Society