RANKING · 2010 CENSUS · 63 SHOWN OF 63

Most population lost, Colorado counties · 2010

Colorado counties that lost the most residents from the 2000 census to 2010, by raw count of people rather than percentage. This list covers the 63 counties in Colorado that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01Prowers County, COCO11,884-1,932−270%

02Otero County, COCO17,683-1,480−1275%

03Huerfano County, COCO7,011-1,151−162%

04Baca County, COCO3,347-729+1769%

05Lincoln County, COCO5,645-620−140%

06Lake County, COCO7,552-502−128%

07Rio Grande County, COCO11,087-431−126%

08Cheyenne County, COCO1,713-395+138%

09Sedgwick County, COCO2,247-368−746%

10Clear Creek County, COCO8,994-234−114%

11Kiowa County, COCO1,412-224+239%

12Jackson County, COCO1,211-183+554%

13Conejos County, COCO7,529-144−115%

14Costilla County, COCO3,679-139−129%

15Mineral County, COCO910-119−144%

16Washington County, COCO4,732-112−198%

17Phillips County, COCO4,420-38−113%

18Hinsdale County, COCO753+53−84%

19San Juan County, COCO813+141−175%

20Saguache County, COCO6,732+191−85%

21Yuma County, COCO9,896+202−77%

22Dolores County, COCO2,466+220−35%

23Kit Carson County, COCO7,069+259−70%

24Las Animas County, COCO14,391+300−79%

25Crowley County, COCO5,677+305−81%

26Alamosa County, COCO16,688+479−64%

27Bent County, COCO5,716+501−47%

28Moffat County, COCO13,122+611−67%

29Fremont County, COCO50,039+679−95%

30Rio Blanco County, COCO6,683+680+4757%

31Gilpin County, COCO6,073+684−59%

32Ouray County, COCO5,265+694−52%

33Custer County, COCO5,590+752−52%

34San Miguel County, COCO7,753+765−74%

35Morgan County, COCO30,306+988−81%

36Gunnison County, COCO17,439+1,368−63%

37Chaffee County, COCO20,831+1,567−56%

38Park County, COCO18,314+1,683−77%

39Montezuma County, COCO26,678+1,705−67%

40Archuleta County, COCO14,306+2,186−52%

41Logan County, COCO20,654+2,205−25%

42Pitkin County, COCO16,625+2,276+3%

43Grand County, COCO16,496+2,401−46%

44Teller County, COCO24,756+2,795−65%

45Delta County, COCO32,178+3,118−55%

46Elbert County, COCO30,534+3,214−69%

47Boulder County, COCO328,560+3,279−95%

48Routt County, COCO25,329+3,819−32%

49Summit County, COCO31,517+4,446−58%

50La Plata County, COCO56,898+7,393−37%

51Jefferson County, COCO580,451+7,487−92%

52Montrose County, COCO44,591+7,844−13%

53Eagle County, COCO54,291+10,538−47%

54Garfield County, COCO63,474+12,598−9%

55Pueblo County, COCO169,277+17,591−5%

56Mesa County, COCO162,845+30,468+32%

57Denver County, COCO740,613+45,522−48%

58Larimer County, COCO377,292+48,136−26%

59Weld County, COCO378,426+71,889+46%

60Adams County, COCO554,668+77,746−21%

61Arapahoe County, COCO673,820+84,036−13%

62El Paso County, COCO757,040+105,334−12%

63Douglas County, COCO399,396+109,699−5%

SHOWING 1–63 OF 63

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS