RANKING · 2025 ESTIMATES · 64 SHOWN OF 64

Most densely populated, Colorado counties

Colorado counties ranked by residents per square mile (2025). This list covers the 64 counties in Colorado that qualify, ranked against each other statewide. The median across all 64 is 11.

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SAME RANKING BYCities States Metros

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01Denver County, COCO740,6134,838+34%

02Broomfield County, COCO79,1742,402–

03Arapahoe County, COCO673,820845+38%

04Jefferson County, COCO580,451759+10%

05▲1Adams County, COCO554,668475+52%

06▲1Douglas County, COCO399,396475+127%

07▼2Boulder County, COCO328,560452+13%

08El Paso County, COCO757,040356+46%

09Larimer County, COCO377,292145+50%

10Weld County, COCO378,42695+109%

11Pueblo County, COCO169,27771+20%

12Summit County, COCO31,51752+34%

13Mesa County, COCO162,84549+40%

14Teller County, COCO24,75644+20%

15Gilpin County, COCO6,07340+28%

16▲1La Plata County, COCO56,89834+29%

17▲1Fremont County, COCO50,03933+8%

18▼2Eagle County, COCO54,29132+30%

19Delta County, COCO32,17828+16%

20▲1Morgan County, COCO30,30624+12%

21▲1Alamosa County, COCO16,68823+12%

22▼2Clear Creek County, COCO8,99423−4%

23Garfield County, COCO63,47422+45%

24▲1Chaffee County, COCO20,83121+28%

25▼1Lake County, COCO7,55220−3%

26Montrose County, COCO44,59120+33%

27Pitkin County, COCO16,62517+12%

28▲1Elbert County, COCO30,53417+54%

29▼1Otero County, COCO17,68314−13%

30Montezuma County, COCO26,67813+12%

31Rio Grande County, COCO11,08712−11%

32Logan County, COCO20,65411+1%

33Routt County, COCO25,32911+29%

34Archuleta County, COCO14,30611+45%

35Ouray County, COCO5,26510+41%

36Grand County, COCO16,4969+33%

37Park County, COCO18,3148+26%

38▲3Custer County, COCO5,5908+60%

39Prowers County, COCO11,8847−18%

40▼2Crowley County, COCO5,6777+3%

41▼1Phillips County, COCO4,4206−1%

42San Miguel County, COCO7,7536+18%

43Conejos County, COCO7,5296−10%

44Gunnison County, COCO17,4395+25%

45▲1Huerfano County, COCO7,0114−11%

46▲1Yuma County, COCO9,8964+1%

47▼2Sedgwick County, COCO2,2474−18%

48Bent County, COCO5,7164−5%

49Kit Carson County, COCO7,0693−12%

50Las Animas County, COCO14,3913−5%

51Costilla County, COCO3,67930%

52Moffat County, COCO13,12230%

53▲1Dolores County, COCO2,4662+34%

54▼1Lincoln County, COCO5,6452−7%

55▲1Saguache County, COCO6,7322+14%

56▲2San Juan County, COCO8132+46%

57▼2Rio Blanco County, COCO6,6832+12%

58▼1Washington County, COCO4,7322−4%

59Baca County, COCO3,3471−26%

60Mineral County, COCO9101+10%

61Cheyenne County, COCO1,7131−23%

62▲1Kiowa County, COCO1,4121−13%

63▼1Jackson County, COCO1,2111−23%

64Hinsdale County, COCO7531−5%

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