Colorado Counties

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

Amusement, Carousel, Amusement Park


County Seat: Brighton 1902-11-15

Population: 519,572

Area: 1,182.29 sq mi

Alamosa County

Potato Field, Aroostook County

Formed: 1913-03-08

County Seat: Alamosa

Population: 16,376

Area: 723.21 sq mi

Arapahoe County

House, Roof, Blue, Country, County, Home

Formed: 1861-11-01

County Seat: Littleton 

Population: 655,070 

Area:804.41 sq mi

Archuleta County

Mount St Helens, Volcanic Eruption

Formed: 1885-04-14

County Seat: Pagosa Springs 

Population: 13,359 

Area: 1,354.53 sq mi

Baca County

Village, Agriculture, Valley, Vietnam

Formed: 1889-04-16

County Seat: Springfield 

Population: 3,506 

Area: 2,558.48 sq mi

Bent County

Agriculture, Green, Rice, Asia, Bali

Formed: 1870-02-11

County Seat: Las Animas

Population: 5,650

Area: 1,541.07 sq mi

Boulder County

Sunset, Dawn, Nature, Dusk, Sun, Sky

Formed: 1861-11-01

County Seat: Boulder 

Population: 330,758 

Area:740.48 sq mi

City and County of Broomfield

Mansion, England, Estate, Country House

Formed: 2001-11-15

County Seat: Broomfield 

Population: 74,112

Area: 33.57 sq mi

Chaffee County

Carnival Rides, Night, Ferris Wheel

Formed: 1879-02-10

County Seat: Salida 

Population: 19,476

Area: 1,014.12 sq mi

Cheyenne County

Farm Yard, Farm, Nature, Farmhouse, Fall

Formed: 1889-03-25

County Seat: Cheyenne Wells 

Population: 1,748 

Area: 1,781.90 sq mi

Clear Creek County

Mansion, England, Estate, Country House

Formed: 1861-11-01

County Seat: Georgetown

Population: 9,397

Area: 396.53 sq mi

Conejos County

Agriculture, Asia, Go Back, Black


County Seat: Conejos 


Area: 1,290.22 sq mi

Costilla County

Carnival, Summer, Ferris Wheel, Holiday


County Seat: San Luis 

Population: 3,499 

Area: 1,229.38 sq mi

Crowley County

Agriculture, Asia, Bali, Cambodia, China


County Seat: Ordway

Population: 5,922 

Area: 800.27 sq mi

Custer County

Barn, Rustic, Barns, Ohio, Digital Art

Formed: 1877-03-09

County Seat: Westcliffe

Population: 4,704

Area: 739.24 sq mi

Delta County

Ireland, Forest, Nature, Green, Irish

Formed: 1883-02-11

County Seat: Delta 

Population: 31,196 

Area: 1,149.44 sq mi 

City and County of Denver

Sunset, Dawn, Nature, Dusk, Sun, Heaven

Formed: 1883-02-11

County Seat: Delta 

Population: 31,196 

Area: 1,149.44 sq mi 

Dolores County

Landscape, Ireland, Killarney

Formed: 1881-03-04

County Seat: Dove Creek

Population: 2,326

Area: 1,076.93 sq mi

Douglas County

Barn, Rustic, Barns, Ohio, Digital Art

Formed: 1861-11-01

County Seat: Castle Rock

Population: 357,978 

Area: 842.30 sq mi

Eagle County

Mount Shuksan, Mountain, Landscape

Formed: 1861-02-01

County Seat: Eagle 

Population: 55,731 

Area: 1,700.76 sq mi

El Paso County

Path, Wooden Track, Wooden Plank Path

Formed: 1861-11-01

County Seat: Colorado Springs 


Area: 2,128.60 sq mi

Elbert County

Yorkshire Rose, County, England

Formed: 1874-02-02

County Seat: Kiowa

Population: 26,062

Area: 1,849.08 sq mi

Fremont County

Usa, America, North America, Moose

Formed: 1861-11-01

County Seat: Cañon City 

Population: 48,939

Area: 1,533.09 sq mi

Garfield County

Gas Station, Workshop, Garage, Old

Formed: 1883-02-10

County Seat: Glenwood Springs

Population: 61,685

Area: 2,958.23 sq mi

Gilpin County

Montana, Barn, Landscape, Scenic, Hdr

Formed: 1861-11-01

County Seat: Central City

Population: 5,808

Area: 150.15 sq mi

Grand County

Park, Parklandschaft, English Garden

Formed: 1874-02-02

County Seat: Hot Sulphur Springs

Population: 15,717

Area: 1,868.53 sq mi

Gunnison County

Religion, Grave Facility, Brown Hill

Formed: 1877-03-09

County Seat: Gunnison

Population: 16,918

Area: 3,259.22 sq mi

Hinsdale County

Tomb, Portal, Dolmen, Stone, Burial

Formed: 1874-02-10

County Seat: Lake City

Population: 788

Area: 1,123.35 sq mi

Huerfano County

Mount Edgcumbe House, Mansion

Formed: 1861-11-01

County Seat: Walsenburg

Population: 6,820

Area: 1,592.37 sq mi

Jackson County

Quilt, Storm, Storm Clouds, Sun

Formed: 1909-05-05

County Seat: Walden 

Population: 1,379

Area: 1,619.75 sq mi

Jefferson County

Mansion, Villa, House, Architecture

Formed: 1861-11-01

County Seat: Golden

Population: 582,910

Area: 772.85 sq mi

Kiowa County

Mansion, Villa, House, Architecture

Formed: 1889-04-11

County Seat: Eads

Population: 1,446

Area: 1,785.90 sq mi

Kit Carson County

Barn, Rustic, Barns, Ohio, Digital Art

Formed: 1889-04-11

County Seat: Burlington 

Population: 7,087

Area: 2,162.43 sq mi

La Plata County

Giants Causeway, Northern Ireland

Formed: 1874-02-10

County Seat: Durango

Population: 55,638

Area: 1,700.44 sq mi

Lake County

Outdoor, Forest, Foliage, Park, Green

Formed: 1861-11-01

County Seat: Leadville 

Population: 7,436

Area: 383.55 sq mi

Larimer County

Mount St Helens, Volcano, Mountain

Formed: 1861-11-01

County Seat: Fort Collins 

Population: 359,066

Area: 2,631.75 sq mi

Las Animas County

Mount Edgcumbe House, Mansion, Towers

Formed: 1866-02-09

County Seat: Trinidad

Population: 14,555

Area: 4,773.27 sq mi

Lincoln County

Quilt, Quilt Barn, Windmill, Barn

Formed: 1889-04-11

County Seat: Hugo

Population: 5,675

Area: 2,585.21 sq mi

Logan County

Two Track, Lane, Scenery, Trees

Formed: 1887-02-25

County Seat: Sterling

Population: 21,528 

Area: 1,845.31 sq mi

Mesa County

Barn, Rustic, Barns, Swing, Broken Swing

Formed: 1883-02-14

County Seat: Grand Junction

Population: 155,703 

Area: 3,345.69 sq mi

Mineral County

Winter, City, Snow, Hungary, Building


County Seat: Creede

Population: 865

Area: 878.16 sq mi

Moffat County

Away, Ireland, Abandoned

Formed: 1911-02-27

County Seat: Craig

Population: 13,292 

Area: 4,755.86 sq mi

Montezuma County

Doc Ryburns House, Bannack, State, Park

Formed: 1889-04-16

County Seat: Cortez

Population: 25,849 

Area: 2,035.80 sq mi

Montrose County

Rock, Insight, Canyon, Outlook


County Seat: Montrose

Population: 42,679

Area: 2,246.43 sq mi

Morgan County

Rock, Insight, Canyon, Outlook

Formed: 1889-02-19

County Seat: Fort Morgan

Population: 29,111

Area: 1,293.83 sq mi

Otero County

Rock, Insight, Canyon, Outlook

Formed: 1889-03-25

County Seat: La Junta


Area: 1,267.66 sq mi

Ouray County

Pinwheels, Energy, Wind Power

Formed: 1877-01-18

County Seat: Ouray 

Population: 4,874 

Area: 542.30 sq mi

Park County

Camping Tipi, Campground, Tent, Tipi

Formed: 1861-11-01

County Seat: Fairplay 

Population: 17,390 

Area: 2,209.36 sq mi

Phillips County

Scenery, Sunrise, Trees, Autumn, Bird

Formed: 1889-03-27

County Seat: Holyoke 

Population: 4,530

Area: 688.30 sq mi

Pitkin County

Scenery, Sunrise, Trees, Autumn, Bird

Formed: 1881-02-23

County Seat: Aspen 

Population: 17,358

Area: 970.37 sq mi

Prowers County

Barn, Rustic, Barns, Ohio, Digital Art

Formed: 1889-04-11

County Seat: Lamar 

Population: 11,999 

Area: 1,645.37 sq mi

Pueblo County

Pingyuan County, Guangdong

Formed: 1861-11-01

County Seat:Pueblo 

Population: 168,162

Area: 2,396.77 sq mi

Rio Blanco County

Pingyuan County, Guangdong

Formed: 1889-03-25

County Seat: Meeker  

Population: 6,529 

Area: 3,226.24 sq mi

Rio Grande County

River, Rapids, Canyon, Water, Nature

Formed: 1874-02-10

County Seat: Del Norte 

Population: 11,539 

Area: 913.10 sq mi

Routt County

Barn, Rustic, Barns, Morning, Dawn


County Seat: Steamboat Springs 

Population: 24,829

Area: 2,362.11 sq mi

Saguache County

Barn, Rustic, Barns, Morning, Dawn

Formed: 1866-12-29

County Seat: Saguache 

Population: 6,368 

Area: 3,168.32 sq mi

San Juan County

Barn, Rustic, Barns, Morning, Dawn

Formed: 1876-01-31

County Seat: Silverton


Area: 388.99 sq mi

San Miguel County

Breakthrough, Cliff, Cliffs, Sea, Water

Formed: 1883-03-02

County Seat: Telluride 1883-03-02

Population: 8,072

Area: 1,290.76 sq mi

Sedgwick County

Farm Market Beans, Beans, Green, Dane

Formed: 1883-03-02

County Seat: Telluride 1883-03-02


Area: 548.83 sq mi

Summit County

Scenery, 3D, Trees, Artistic, Art Print

Formed: 1861-11-01

County Seat: Breckenridge

Population: 31,055 

Area: 618.92 sq mi

Teller County

Train, Railroad, Rails, Train Ride

Formed: 1899-03-23

County Seat: Cripple Creek

Population: 24,710

Area: 558.58 sq mi

Washington County

Summer, Virginia, Northern Virginia

Formed: 1887-02-09

County Seat: kron 

Population: 4,817

Area:2,522.90 sq mi

Weld County

Summer, Virginia, Northern Virginia

Formed: 1861-11-01

County Seat: Greeley 

Population: 328,981

Area: 4,013.84 sq mi

Yuma County

Sunset, Weeds, Warm, Glow, Green

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 NameCounty SeatFIPS CodeYear FormedPopulation as of 2019
Adams CountyBrighton0011902517,421
Alamosa CountyAlamosa003191316,107
Arapahoe CountyLittleton0051861656,590
Archuleta CountyPagosa Springs007188513,253
Baca CountySpringfield00918893,561
Bent CountyLas Animas01118705,787
Boulder CountyBoulder0131861326,196
Broomfield CountyBroomfield014200167,886
Chaffee CountySalida015187919,557
Cheyenne CountyCheyenne Wells01718892,026
Clear Creek CountyGeorgetown01918619,700
Conejos CountyConejos02118618,128
Costilla CountySan Luis02318613,745
Crowley CountyOrdway02519115,754
Custer CountyWestcliffe02718774,776
Delta CountyDelta029188330,565
Denver CountyDenver0311902735,538
Dolores CountyDove Creek03318811,857
Douglas CountyCastle Rock0351861351,154
Eagle CountyEagle037188355,127
El Paso CountyColorado Springs0411861720,403
Elbert CountyKiowa039187426,729
Fremont CountyCañon City043186147,839
Garfield CountyGlenwood Springs045188360,061
Gilpin CountyCentral City04718616,243
Grand CountyHot Sulphur Springs049187415,303
Gunnison CountyGunnison051187716,802
Hinsdale CountyLake City0531874857
Huerfano CountyWalsenburg05518616,679
Jackson CountyWalden05719091,261
Jefferson CountyGolden0591861582,881
Kiowa CountyEads06118891,489
Kit Carson CountyBurlington06318897,447
La Plata CountyDurango067187456,221
Lake CountyLeadville06518617,751
Larimer CountyFort Collins0691861356,899
Las Animas CountyTrinidad071186614,266
Lincoln CountyHugo07318895,585
Logan CountySterling075188722,409
Mesa CountyGrand Junction0771883154,210
Mineral CountyCreede0791893824
Moffat CountyCraig081191113,283
Montezuma CountyCortez083188926,031
Montrose CountyMontrose085188342,758
Morgan CountyFort Morgan087188929,068
Otero CountyLa Junta089188918,282
Ouray CountyOuray09118774,952
Park CountyFairplay093186118,845
Phillips CountyHolyoke09518894,290
Pitkin CountyAspen097188117,767
Prowers CountyLamar099188912,022
Pueblo CountyPueblo1011861168,424
Rio Blanco CountyMeeker10318896,384
Rio Grande CountyDel Norte105187411,305
Routt CountySteamboat Springs107187725,638
Saguache CountySaguache10918666,592
San Juan CountySilverton1111876589
San Miguel CountyTelluride11318838,049
Sedgwick CountyJulesburg11518892,322
Summit CountyBreckenridge117186131,011
Teller CountyCripple Creek119189925,388
Washington CountyAkron12118874,868
Weld CountyGreeley1231861324,492
Yuma CountyWray125188910,003


10 Most Populous Colorado Counties

1. Denver County  

colorado counties

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 

colorado counties

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

colorado counties

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 

colorado counties

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  

colorado counties

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  

colorado counties

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  

colorado counties

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  

colorado counties

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.  



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