RANKING · 2010 CENSUS · 64 SHOWN OF 64

Most densely populated, Colorado counties · 2010

Colorado counties ranked by residents per square mile (2023). This list covers the 64 counties in Colorado that qualify, ranked against each other statewide.

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YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01Denver County, COCO740,6133,921+8%

02Broomfield County, COCO79,1741,695–

03Arapahoe County, COCO673,820717+17%

04Jefferson County, COCO580,451699+1%

05Boulder County, COCO328,560406+1%

06Adams County, COCO554,668378+21%

07Douglas County, COCO399,396339+62%

08El Paso County, COCO757,040293+20%

09Larimer County, COCO377,292115+19%

10Pueblo County, COCO169,27767+12%

11Weld County, COCO378,42663+40%

12Summit County, COCO31,51746+19%

13Mesa County, COCO162,84544+26%

14Teller County, COCO24,75642+14%

15Gilpin County, COCO6,07336+14%

16Eagle County, COCO54,29131+25%

17Fremont County, COCO50,03931+1%

18La Plata County, COCO56,89830+17%

19Delta County, COCO32,17827+11%

20Clear Creek County, COCO8,99423−3%

21Morgan County, COCO30,30622+4%

22Alamosa County, COCO16,68821+3%

23Lake County, COCO7,55219−6%

24Garfield County, COCO63,47419+29%

25Montrose County, COCO44,59118+23%

26Pitkin County, COCO16,62518+15%

27Chaffee County, COCO20,83118+10%

28Otero County, COCO17,68315−7%

29Rio Grande County, COCO11,08713−3%

30Montezuma County, COCO26,67813+7%

31Elbert County, COCO30,53412+16%

32Logan County, COCO20,65412+11%

33Routt County, COCO25,32910+19%

34Archuleta County, COCO14,3069+22%

35Ouray County, COCO5,2658+19%

36Grand County, COCO16,4968+19%

37Prowers County, COCO11,8848−13%

38Crowley County, COCO5,6777+6%

39Park County, COCO18,3147+12%

40Phillips County, COCO4,4206−1%

41Conejos County, COCO7,5296−2%

42Custer County, COCO5,5906+21%

43San Miguel County, COCO7,7536+12%

44Gunnison County, COCO17,4395+10%

45Sedgwick County, COCO2,2474−13%

46Bent County, COCO5,7164+8%

47Yuma County, COCO9,8964+2%

48Huerfano County, COCO7,0114−15%

49Kit Carson County, COCO7,0694+3%

50Las Animas County, COCO14,3913+2%

51Moffat County, COCO13,1223+5%

52Costilla County, COCO3,6793−4%

53Lincoln County, COCO5,6452−10%

54Rio Blanco County, COCO6,6832+11%

55Dolores County, COCO2,4662+12%

56Saguache County, COCO6,7322+3%

57Washington County, COCO4,7322−2%

58San Juan County, COCO8132+25%

59Baca County, COCO3,3471−16%

60Cheyenne County, COCO1,7131−18%

61Jackson County, COCO1,2111−12%

62Mineral County, COCO9101−14%

63Kiowa County, COCO1,4121−14%

64Hinsdale County, COCO7531+7%

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UPDATED 2026-06-02 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES