RANKING · 2025 ESTIMATES · 64 SHOWN OF 64

Largest by population, Colorado counties

The most populous Colorado counties as of the 2025 population estimates. This list covers the 64 counties in Colorado that qualify, ranked against each other statewide. The median across all 64 is 16,496.

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SAME RANKING BYCities States Metros ZIP codes

YEAR1990 2000 2010 2020 2025

RANKPLACESTATETOTAL POPULATIONVS 2000

01El Paso County, COCO757,040+46%

02Denver County, COCO740,613+34%

03Arapahoe County, COCO673,820+38%

04Jefferson County, COCO580,451+10%

05Adams County, COCO554,668+52%

06▲1Douglas County, COCO399,396+127%

07▲2Weld County, COCO378,426+109%

08▼2Larimer County, COCO377,292+50%

09▼1Boulder County, COCO328,560+13%

10Pueblo County, COCO169,277+20%

11Mesa County, COCO162,845+40%

12Broomfield County, COCO79,174–

13Garfield County, COCO63,474+45%

14▲1La Plata County, COCO56,898+29%

15▼1Eagle County, COCO54,291+30%

16Fremont County, COCO50,039+8%

17Montrose County, COCO44,591+33%

18Delta County, COCO32,178+16%

19Summit County, COCO31,517+34%

20▲1Elbert County, COCO30,534+54%

21▼1Morgan County, COCO30,306+12%

22Montezuma County, COCO26,678+12%

23Routt County, COCO25,329+29%

24Teller County, COCO24,756+20%

25▲1Chaffee County, COCO20,831+28%

26▼1Logan County, COCO20,654+1%

27▲1Park County, COCO18,314+26%

28▼1Otero County, COCO17,683−13%

29▲1Gunnison County, COCO17,439+25%

30▲1Alamosa County, COCO16,688+12%

31▼2Pitkin County, COCO16,625+12%

32Grand County, COCO16,496+33%

33Las Animas County, COCO14,391−5%

34Archuleta County, COCO14,306+45%

35Moffat County, COCO13,1220%

36Prowers County, COCO11,884−18%

37Rio Grande County, COCO11,087−11%

38Yuma County, COCO9,896+1%

39Clear Creek County, COCO8,994−4%

40San Miguel County, COCO7,753+18%

41▲1Lake County, COCO7,552−3%

42▼1Conejos County, COCO7,529−10%

43Kit Carson County, COCO7,069−12%

44Huerfano County, COCO7,011−11%

45▲1Saguache County, COCO6,732+14%

46▼1Rio Blanco County, COCO6,683+12%

47▲1Gilpin County, COCO6,073+28%

48▲2Bent County, COCO5,716−5%

49▼2Crowley County, COCO5,677+3%

50▼1Lincoln County, COCO5,645−7%

51▲2Custer County, COCO5,590+60%

52▼1Ouray County, COCO5,265+41%

53▼1Washington County, COCO4,732−4%

54Phillips County, COCO4,420−1%

55▲1Costilla County, COCO3,6790%

56▼1Baca County, COCO3,347−26%

57▲1Dolores County, COCO2,466+34%

58▼1Sedgwick County, COCO2,247−18%

59Cheyenne County, COCO1,713−23%

60Kiowa County, COCO1,412−13%

61Jackson County, COCO1,211−23%

62Mineral County, COCO910+10%

63▲1San Juan County, COCO813+46%

64▼1Hinsdale County, COCO753−5%

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU POPULATION ESTIMATES