RANKING · 2020 CENSUS · 64 SHOWN OF 64

Most densely populated, Colorado counties · 2020

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, COCO740,6134,674+29%

02Broomfield County, COCO79,1742,248–

03Arapahoe County, COCO673,820821+34%

04Jefferson County, COCO580,451763+11%

05Boulder County, COCO328,560455+14%

06Adams County, COCO554,668445+43%

07Douglas County, COCO399,396426+104%

08El Paso County, COCO757,040343+41%

09Larimer County, COCO377,292138+43%

10Weld County, COCO378,42683+82%

11Pueblo County, COCO169,27770+19%

12Summit County, COCO31,51751+32%

13Mesa County, COCO162,84547+34%

14Teller County, COCO24,75644+20%

15Gilpin County, COCO6,07339+22%

16Eagle County, COCO54,29133+34%

17La Plata County, COCO56,89833+27%

18Fremont County, COCO50,03932+6%

19Delta County, COCO32,17827+12%

20Clear Creek County, COCO8,99424+1%

21Morgan County, COCO30,30623+7%

22Alamosa County, COCO16,68823+9%

23Garfield County, COCO63,47421+41%

24Lake County, COCO7,55220−5%

25Chaffee County, COCO20,83119+20%

26Montrose County, COCO44,59119+28%

27Pitkin County, COCO16,62518+17%

28Otero County, COCO17,68315−8%

29Elbert County, COCO30,53414+31%

30Montezuma County, COCO26,67813+8%

31Rio Grande County, COCO11,08713−7%

32Logan County, COCO20,65412+5%

33Routt County, COCO25,32911+26%

34Archuleta County, COCO14,30610+35%

35Ouray County, COCO5,2659+30%

36Grand County, COCO16,4969+26%

37Park County, COCO18,3148+20%

38Crowley County, COCO5,6778+7%

39Prowers County, COCO11,8847−17%

40Phillips County, COCO4,4207+1%

41Custer County, COCO5,5906+34%

42San Miguel County, COCO7,7536+22%

43Conejos County, COCO7,5296−11%

44Gunnison County, COCO17,4395+21%

45Sedgwick County, COCO2,2474−12%

46Huerfano County, COCO7,0114−13%

47Yuma County, COCO9,8964+1%

48Bent County, COCO5,7164−6%

49Kit Carson County, COCO7,0693−12%

50Las Animas County, COCO14,3913−4%

51Costilla County, COCO3,6793−4%

52Moffat County, COCO13,1223+1%

53Lincoln County, COCO5,6452−7%

54Dolores County, COCO2,4662+26%

55Rio Blanco County, COCO6,6832+9%

56Saguache County, COCO6,7322+8%

57Washington County, COCO4,7322−2%

58San Juan County, COCO8132+26%

59Baca County, COCO3,3471−22%

60Mineral County, COCO9101+4%

61Cheyenne County, COCO1,7131−22%

62Jackson County, COCO1,2111−13%

63Kiowa County, COCO1,4121−11%

64Hinsdale County, COCO7531−0%

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