Colorado Counties, That is the content of today’s article. Colorado has 64 Counties. It started off at first with only 17 and kept on growing until it got to 26 on the 1st of August, 1861, when Colorado became a state. Later on, more Counties were created from each of the already existing ones making the number increase.
Today, we have 64 Counties in Colorado showing that 38 Counties after Colorado became a state in 1861. Looking at this content you will observe that during the formation of the counties, 2-4 counties are created on the same day making it possible for Colorado to have a total number of 64 counties in a short period of time.
Below is a list of Colorado Counties arranged in alphabetical order with their Year of Creation, County Seat, Population, and Area.
Table of Contents
64 A – Z Lists of Colorado Counties, Year Formed, Population, County Seat, and Area
Adams County
Formed:1902-11-15
County Seat: Brighton 1902-11-15
Population: 519,572
Area: 1,182.29 sq mi
Alamosa County
Formed: 1913-03-08
County Seat: Alamosa
Population: 16,376
Area: 723.21 sq mi
Arapahoe County
Formed: 1861-11-01
County Seat: Littleton
Population: 655,070
Area:804.41 sq mi
Archuleta County
Formed: 1885-04-14
County Seat: Pagosa Springs
Population: 13,359
Area: 1,354.53 sq mi
Baca County
Formed: 1889-04-16
County Seat: Springfield
Population: 3,506
Area: 2,558.48 sq mi
Bent County
Formed: 1870-02-11
County Seat: Las Animas
Population: 5,650
Area: 1,541.07 sq mi
Boulder County
Formed: 1861-11-01
County Seat: Boulder
Population: 330,758
Area:740.48 sq mi
City and County of Broomfield
Formed: 2001-11-15
County Seat: Broomfield
Population: 74,112
Area: 33.57 sq mi
Chaffee County
Formed: 1879-02-10
County Seat: Salida
Population: 19,476
Area: 1,014.12 sq mi
Cheyenne County
Formed: 1889-03-25
County Seat: Cheyenne Wells
Population: 1,748
Area: 1,781.90 sq mi
Clear Creek County
Formed: 1861-11-01
County Seat: Georgetown
Population: 9,397
Area: 396.53 sq mi
Conejos County
Formed:1861-11-01
County Seat: Conejos
Population:7,461
Area: 1,290.22 sq mi
Costilla County
Formed:1861-11-01
County Seat: San Luis
Population: 3,499
Area: 1,229.38 sq mi
Crowley County
Formed:1911-05-29
County Seat: Ordway
Population: 5,922
Area: 800.27 sq mi
Custer County
Formed: 1877-03-09
County Seat: Westcliffe
Population: 4,704
Area: 739.24 sq mi
Delta County
Formed: 1883-02-11
County Seat: Delta
Population: 31,196
Area: 1,149.44 sq mi
City and County of Denver
Formed: 1883-02-11
County Seat: Delta
Population: 31,196
Area: 1,149.44 sq mi
Dolores County
Formed: 1881-03-04
County Seat: Dove Creek
Population: 2,326
Area: 1,076.93 sq mi
Douglas County
Formed: 1861-11-01
County Seat: Castle Rock
Population: 357,978
Area: 842.30 sq mi
Eagle County
Formed: 1861-02-01
County Seat: Eagle
Population: 55,731
Area: 1,700.76 sq mi
El Paso County
Formed: 1861-11-01
County Seat: Colorado Springs
Population:730,395
Area: 2,128.60 sq mi
Elbert County
Formed: 1874-02-02
County Seat: Kiowa
Population: 26,062
Area: 1,849.08 sq mi
Fremont County
Formed: 1861-11-01
County Seat: Cañon City
Population: 48,939
Area: 1,533.09 sq mi
Garfield County
Formed: 1883-02-10
County Seat: Glenwood Springs
Population: 61,685
Area: 2,958.23 sq mi
Gilpin County
Formed: 1861-11-01
County Seat: Central City
Population: 5,808
Area: 150.15 sq mi
Grand County
Formed: 1874-02-02
County Seat: Hot Sulphur Springs
Population: 15,717
Area: 1,868.53 sq mi
Gunnison County
Formed: 1877-03-09
County Seat: Gunnison
Population: 16,918
Area: 3,259.22 sq mi
Hinsdale County
Formed: 1874-02-10
County Seat: Lake City
Population: 788
Area: 1,123.35 sq mi
Huerfano County
Formed: 1861-11-01
County Seat: Walsenburg
Population: 6,820
Area: 1,592.37 sq mi
Jackson County
Formed: 1909-05-05
County Seat: Walden
Population: 1,379
Area: 1,619.75 sq mi
Jefferson County
Formed: 1861-11-01
County Seat: Golden
Population: 582,910
Area: 772.85 sq mi
Kiowa County
Formed: 1889-04-11
County Seat: Eads
Population: 1,446
Area: 1,785.90 sq mi
Kit Carson County
Formed: 1889-04-11
County Seat: Burlington
Population: 7,087
Area: 2,162.43 sq mi
La Plata County
Formed: 1874-02-10
County Seat: Durango
Population: 55,638
Area: 1,700.44 sq mi
Lake County
Formed: 1861-11-01
County Seat: Leadville
Population: 7,436
Area: 383.55 sq mi
Larimer County
Formed: 1861-11-01
County Seat: Fort Collins
Population: 359,066
Area: 2,631.75 sq mi
Las Animas County
Formed: 1866-02-09
County Seat: Trinidad
Population: 14,555
Area: 4,773.27 sq mi
Lincoln County
Formed: 1889-04-11
County Seat: Hugo
Population: 5,675
Area: 2,585.21 sq mi
Logan County
Formed: 1887-02-25
County Seat: Sterling
Population: 21,528
Area: 1,845.31 sq mi
Mesa County
Formed: 1883-02-14
County Seat: Grand Junction
Population: 155,703
Area: 3,345.69 sq mi
Mineral County
Formed:1893-03-27
County Seat: Creede
Population: 865
Area: 878.16 sq mi
Moffat County
Formed: 1911-02-27
County Seat: Craig
Population: 13,292
Area: 4,755.86 sq mi
Montezuma County
Formed: 1889-04-16
County Seat: Cortez
Population: 25,849
Area: 2,035.80 sq mi
Montrose County
Formed:1883-02-11
County Seat: Montrose
Population: 42,679
Area: 2,246.43 sq mi
Morgan County
Formed: 1889-02-19
County Seat: Fort Morgan
Population: 29,111
Area: 1,293.83 sq mi
Otero County
Formed: 1889-03-25
County Seat: La Junta
Population:18,690
Area: 1,267.66 sq mi
Ouray County
Formed: 1877-01-18
County Seat: Ouray
Population: 4,874
Area: 542.30 sq mi
Park County
Formed: 1861-11-01
County Seat: Fairplay
Population: 17,390
Area: 2,209.36 sq mi
Phillips County
Formed: 1889-03-27
County Seat: Holyoke
Population: 4,530
Area: 688.30 sq mi
Pitkin County
Formed: 1881-02-23
County Seat: Aspen
Population: 17,358
Area: 970.37 sq mi
Prowers County
Formed: 1889-04-11
County Seat: Lamar
Population: 11,999
Area: 1,645.37 sq mi
Pueblo County
Formed: 1861-11-01
County Seat:Pueblo
Population: 168,162
Area: 2,396.77 sq mi
Rio Blanco County
Formed: 1889-03-25
County Seat: Meeker
Population: 6,529
Area: 3,226.24 sq mi
Rio Grande County
Formed: 1874-02-10
County Seat: Del Norte
Population: 11,539
Area: 913.10 sq mi
Routt County
Formed:1877-01-29
County Seat: Steamboat Springs
Population: 24,829
Area: 2,362.11 sq mi
Saguache County
Formed: 1866-12-29
County Seat: Saguache
Population: 6,368
Area: 3,168.32 sq mi
San Juan County
Formed: 1876-01-31
County Seat: Silverton
Population:705
Area: 388.99 sq mi
San Miguel County
Formed: 1883-03-02
County Seat: Telluride 1883-03-02
Population: 8,072
Area: 1,290.76 sq mi
Sedgwick County
Formed: 1883-03-02
County Seat: Telluride 1883-03-02
Population:2,404
Area: 548.83 sq mi
Summit County
Formed: 1861-11-01
County Seat: Breckenridge
Population: 31,055
Area: 618.92 sq mi
Teller County
Formed: 1899-03-23
County Seat: Cripple Creek
Population: 24,710
Area: 558.58 sq mi
Washington County
Formed: 1887-02-09
County Seat: kron
Population: 4,817
Area:2,522.90 sq mi
Weld County
Formed: 1861-11-01
County Seat: Greeley
Population: 328,981
Area: 4,013.84 sq mi
Yuma County
Formed: 1889-03-15
County Seat: Wray 1889-03-15
Population: 9,988
Area: 2,369.61 sq mi
There are currently 64 counties in the U.S. State of Colorado but before Colorado became a U.S. state in 1876, it had only 26 counties. The number rose to 40 in 1885 after the creation of Archuleta County and eventually to 64 counties in 2001 when Broomfield was consolidated as a city and county.
These Colorado counties are important units of government in the state because there’re no townships or other minor civil divisions.
Out of these 64 counties, two (Broomfield and Denver) have consolidated city and county governments. Each county in Colorado has its own character and sense of identity.
Here is a list of all the counties in Colorado, their FIPS code, year formed, and population.
List of all Colorado Counties
County Name | County Seat | FIPS Code | Year Formed | Population as of 2019 |
Adams County | Brighton | 001 | 1902 | 517,421 |
Alamosa County | Alamosa | 003 | 1913 | 16,107 |
Arapahoe County | Littleton | 005 | 1861 | 656,590 |
Archuleta County | Pagosa Springs | 007 | 1885 | 13,253 |
Baca County | Springfield | 009 | 1889 | 3,561 |
Bent County | Las Animas | 011 | 1870 | 5,787 |
Boulder County | Boulder | 013 | 1861 | 326,196 |
Broomfield County | Broomfield | 014 | 2001 | 67,886 |
Chaffee County | Salida | 015 | 1879 | 19,557 |
Cheyenne County | Cheyenne Wells | 017 | 1889 | 2,026 |
Clear Creek County | Georgetown | 019 | 1861 | 9,700 |
Conejos County | Conejos | 021 | 1861 | 8,128 |
Costilla County | San Luis | 023 | 1861 | 3,745 |
Crowley County | Ordway | 025 | 1911 | 5,754 |
Custer County | Westcliffe | 027 | 1877 | 4,776 |
Delta County | Delta | 029 | 1883 | 30,565 |
Denver County | Denver | 031 | 1902 | 735,538 |
Dolores County | Dove Creek | 033 | 1881 | 1,857 |
Douglas County | Castle Rock | 035 | 1861 | 351,154 |
Eagle County | Eagle | 037 | 1883 | 55,127 |
El Paso County | Colorado Springs | 041 | 1861 | 720,403 |
Elbert County | Kiowa | 039 | 1874 | 26,729 |
Fremont County | Cañon City | 043 | 1861 | 47,839 |
Garfield County | Glenwood Springs | 045 | 1883 | 60,061 |
Gilpin County | Central City | 047 | 1861 | 6,243 |
Grand County | Hot Sulphur Springs | 049 | 1874 | 15,303 |
Gunnison County | Gunnison | 051 | 1877 | 16,802 |
Hinsdale County | Lake City | 053 | 1874 | 857 |
Huerfano County | Walsenburg | 055 | 1861 | 6,679 |
Jackson County | Walden | 057 | 1909 | 1,261 |
Jefferson County | Golden | 059 | 1861 | 582,881 |
Kiowa County | Eads | 061 | 1889 | 1,489 |
Kit Carson County | Burlington | 063 | 1889 | 7,447 |
La Plata County | Durango | 067 | 1874 | 56,221 |
Lake County | Leadville | 065 | 1861 | 7,751 |
Larimer County | Fort Collins | 069 | 1861 | 356,899 |
Las Animas County | Trinidad | 071 | 1866 | 14,266 |
Lincoln County | Hugo | 073 | 1889 | 5,585 |
Logan County | Sterling | 075 | 1887 | 22,409 |
Mesa County | Grand Junction | 077 | 1883 | 154,210 |
Mineral County | Creede | 079 | 1893 | 824 |
Moffat County | Craig | 081 | 1911 | 13,283 |
Montezuma County | Cortez | 083 | 1889 | 26,031 |
Montrose County | Montrose | 085 | 1883 | 42,758 |
Morgan County | Fort Morgan | 087 | 1889 | 29,068 |
Otero County | La Junta | 089 | 1889 | 18,282 |
Ouray County | Ouray | 091 | 1877 | 4,952 |
Park County | Fairplay | 093 | 1861 | 18,845 |
Phillips County | Holyoke | 095 | 1889 | 4,290 |
Pitkin County | Aspen | 097 | 1881 | 17,767 |
Prowers County | Lamar | 099 | 1889 | 12,022 |
Pueblo County | Pueblo | 101 | 1861 | 168,424 |
Rio Blanco County | Meeker | 103 | 1889 | 6,384 |
Rio Grande County | Del Norte | 105 | 1874 | 11,305 |
Routt County | Steamboat Springs | 107 | 1877 | 25,638 |
Saguache County | Saguache | 109 | 1866 | 6,592 |
San Juan County | Silverton | 111 | 1876 | 589 |
San Miguel County | Telluride | 113 | 1883 | 8,049 |
Sedgwick County | Julesburg | 115 | 1889 | 2,322 |
Summit County | Breckenridge | 117 | 1861 | 31,011 |
Teller County | Cripple Creek | 119 | 1899 | 25,388 |
Washington County | Akron | 121 | 1887 | 4,868 |
Weld County | Greeley | 123 | 1861 | 324,492 |
Yuma County | Wray | 125 | 1889 | 10,003 |
10 Most Populous Colorado Counties
1. Denver County

Denver is a consolidated city and a county government. It was established in 1858 as a mining town during the heady days of the Pike’s Peak Gold Rush.
Denver is the capital and the most populous city in Colorado with an estimated population of 735,538. Denver is U.S.’s 19th most populous city and the 5th most populous state capital.
2. El Paso County

El Paso County was founded on November 1, 1861. Its largest city and county seat is Colorado Springs which is the second-most populous city in Colorado.
According to the U.S. Census Bureau, El Paso County’s population as of 2019 was estimated to be 720,403, making it the second-most populous county in Colorado.
El Paso County is home to numerous military sites such as the United States Air Force Academy, Fort Carson Army, North American Aerospace Defense Command (NORAD), Schriever Air Force Base, and Peterson Air Force Base.
3. Arapahoe County

Arapahoe County is the third-most populous county in Colorado with an estimated population of 656,590. It was founded in 1861 and its county seat is Littleton and its largest city is Aurora.
Arapahoe County was named for the Arapaho Native American tribe, who once lived in the region.
4. Jefferson County

Jefferson County was established on November 1, 1861. It is the fourth most populous county in Colorado with an estimated population of 582,881. Its county seat is Golden and its largest city is Lakewood.
Jefferson County’s slogan is the “Gateway to the Rocky Mountains” and it is commonly nicknamed JeffCo.
5. Adams County
Adams County was founded April 15, 1901, and named for Alva Adams an American politician. It is the fifth most populous county in Colorado with an estimated population of 517,421.
Its county seat is Brighton and its largest city is Thornton.
6. Larimer County

Larimer County was founded November 1, 1861, and named for William Larimer, Jr, the founder of Denver. Its county seat and largest city is Fort Collins.
Larimer County is the sixth most populous county in Colorado with an estimated population of 356,899.
7. Douglas County

As of 2019, Douglas County’s population was estimated to be 351,154, making it the seventh most populous county in Colorado.
The largest community in Douglas County is Highlands Ranch and its county seat is Castle Rock. Douglas County was created in 1861 and was named for Stephen A. Douglas.
8. Boulder County

Boulder County was founded in 1861 and named for Boulder City and Boulder Creek. Its largest city and county seat is Boulder.
As of 2019, its population was estimated to be 326,196 making it the eighth most populous county in Colorado.
9. Weld County

Weld County estimated population as of 2019 was 324,492, making it the ninth most populous county in Colorado. It is also the 3rd largest county in Colorado by area covering 4,017 square miles.
Weld County is Colorado’s largest cattle producer, accounting for about half of the state’s total cattle inventory.
It is also one of the largest providers of grains and sugar beets making it one of the richest agricultural counties in the United States.
10. Pueblo County

Pueblo County had a population of 168,424 in 2019, making it the tenth most populous county in Colorado. The county was founded in 1861 and was named for the historic City of Pueblo.
Its county seat and largest city is Pueblo.
Summary
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