Counties in Colorado by population

El Paso County had the highest population of 64 counties in 2020, at 733,721. San Juan County had the lowest, at 710. The median was 15,120 and the figure for Colorado was 5.79 million. Source: the U.S. Census Bureau.

Highest733,721El Paso County
Median15,12064 counties
Colorado5,786,873History

Top 40 counties, 2020

CSVChart (SVG)

El Paso CountyEl Paso County: 733,721 persons733,721Denver CountyDenver County: 717,680 persons717,680Arapahoe CountyArapahoe County: 655,269 persons655,269Jefferson CountyJefferson County: 583,131 persons583,131Adams CountyAdams County: 520,411 persons520,411Douglas CountyDouglas County: 360,315 persons360,315Larimer CountyLarimer County: 359,942 persons359,942Weld CountyWeld County: 331,434 persons331,434Boulder CountyBoulder County: 330,982 persons330,982Pueblo CountyPueblo County: 168,334 persons168,334Mesa CountyMesa County: 156,007 persons156,007Broomfield CountyBroomfield County: 74,482 persons74,482Garfield CountyGarfield County: 61,793 persons61,793La Plata CountyLa Plata County: 55,679 persons55,679Eagle CountyEagle County: 55,657 persons55,657Fremont CountyFremont County: 48,880 persons48,880Montrose CountyMontrose County: 42,825 persons42,825Summit CountySummit County: 31,237 persons31,237Delta CountyDelta County: 31,062 persons31,062Morgan CountyMorgan County: 29,080 persons29,080Elbert CountyElbert County: 26,211 persons26,211Montezuma CountyMontezuma County: 25,890 persons25,890Routt CountyRoutt County: 24,837 persons24,837Teller CountyTeller County: 24,746 persons24,746Logan CountyLogan County: 21,221 persons21,221Chaffee CountyChaffee County: 19,486 persons19,486Otero CountyOtero County: 18,659 persons18,659Park CountyPark County: 17,425 persons17,425Pitkin CountyPitkin County: 17,363 persons17,363Gunnison CountyGunnison County: 16,950 persons16,950Alamosa CountyAlamosa County: 16,377 persons16,377Grand CountyGrand County: 15,748 persons15,748Las Animas CountyLas Animas County: 14,491 persons14,491Archuleta CountyArchuleta County: 13,426 persons13,426Moffat CountyMoffat County: 13,267 persons13,267Prowers CountyProwers County: 12,012 persons12,012Rio Grande CountyRio Grande County: 11,538 persons11,538Yuma CountyYuma County: 9,975 persons9,975Clear Creek CountyClear Creek County: 9,358 persons9,358San Miguel CountySan Miguel County: 8,053 persons8,053
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

Other periods

About this ranking

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (PadrĂ³n). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.

For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.

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Rank Counties in Colorado by population using official data, and cite the source.
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Questions

Which county has the highest population?

El Paso County, with 733,721 in 2020, according to the U.S. Census Bureau.

Which county has the lowest population?

San Juan County, with 710 in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved 2026-10-08.

Population: other rankings

Counties in Colorado: more rankings