RANKING · 1990 CENSUS · 63 SHOWN OF 63

Most densely populated, Colorado counties · 1990

Colorado counties ranked by residents per square mile (1990). This list covers the 63 counties in Colorado that qualify, ranked against each other statewide. The median across all 63 is 6.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest growing Fastest shrinking Most population gained Most population lost Most sparsely populated

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS –

01Denver County, COCO740,6133,055–

02Jefferson County, COCO580,451574–

03Arapahoe County, COCO673,820491–

04Boulder County, COCO328,560310–

05Adams County, COCO554,668227–

06El Paso County, COCO757,040187–

07Douglas County, COCO399,39672–

08Larimer County, COCO377,29272–

09Pueblo County, COCO169,27752–

10Weld County, COCO378,42633–

11Mesa County, COCO162,84528–

12Teller County, COCO24,75622–

13Summit County, COCO31,51721–

14Fremont County, COCO50,03921–

15Gilpin County, COCO6,07320–

16Clear Creek County, COCO8,99419–

17La Plata County, COCO56,89819–

18Alamosa County, COCO16,68819–

19Delta County, COCO32,17818–

20Morgan County, COCO30,30617–

21Otero County, COCO17,68316–

22Lake County, COCO7,55216–

23Pitkin County, COCO16,62513–

24Eagle County, COCO54,29113–

25Chaffee County, COCO20,83113–

26Rio Grande County, COCO11,08712–

27Montrose County, COCO44,59111–

28Garfield County, COCO63,47410–

29Logan County, COCO20,65410–

30Montezuma County, COCO26,6789–

31Prowers County, COCO11,8848–

32Phillips County, COCO4,4206–

33Routt County, COCO25,3296–

34Conejos County, COCO7,5296–

35Elbert County, COCO30,5345–

36Crowley County, COCO5,6775–

37Sedgwick County, COCO2,2475–

38Grand County, COCO16,4964–

39Ouray County, COCO5,2654–

40Archuleta County, COCO14,3064–

41Yuma County, COCO9,8964–

42Huerfano County, COCO7,0114–

43Bent County, COCO5,7163–

44Kit Carson County, COCO7,0693–

45Park County, COCO18,3143–

46Gunnison County, COCO17,4393–

47Las Animas County, COCO14,3913–

48San Miguel County, COCO7,7533–

49Custer County, COCO5,5903–

50Costilla County, COCO3,6793–

51Moffat County, COCO13,1222–

52San Juan County, COCO8132–

53Washington County, COCO4,7322–

54Rio Blanco County, COCO6,6832–

55Baca County, COCO3,3472–

56Lincoln County, COCO5,6452–

57Saguache County, COCO6,7321–

58Dolores County, COCO2,4661–

59Cheyenne County, COCO1,7131–

60Jackson County, COCO1,2111–

61Kiowa County, COCO1,4121–

62Mineral County, COCO9101–

63Hinsdale County, COCO7530–

SHOWING 1–63 OF 63

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU DECENNIAL CENSUS