RANKING · 2010 CENSUS · 63 SHOWN OF 63

Most population gained, Colorado counties · 2010

Colorado counties that added 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

01Douglas County, COCO399,396+109,699−5%

02El Paso County, COCO757,040+105,334−12%

03Arapahoe County, COCO673,820+84,036−13%

04Adams County, COCO554,668+77,746−21%

05Weld County, COCO378,426+71,889+46%

06Larimer County, COCO377,292+48,136−26%

07Denver County, COCO740,613+45,522−48%

08Mesa County, COCO162,845+30,468+32%

09Pueblo County, COCO169,277+17,591−5%

10Garfield County, COCO63,474+12,598−9%

11Eagle County, COCO54,291+10,538−47%

12Montrose County, COCO44,591+7,844−13%

13Jefferson County, COCO580,451+7,487−92%

14La Plata County, COCO56,898+7,393−37%

15Summit County, COCO31,517+4,446−58%

16Routt County, COCO25,329+3,819−32%

17Boulder County, COCO328,560+3,279−95%

18Elbert County, COCO30,534+3,214−69%

19Delta County, COCO32,178+3,118−55%

20Teller County, COCO24,756+2,795−65%

21Grand County, COCO16,496+2,401−46%

22Pitkin County, COCO16,625+2,276+3%

23Logan County, COCO20,654+2,205−25%

24Archuleta County, COCO14,306+2,186−52%

25Montezuma County, COCO26,678+1,705−67%

26Park County, COCO18,314+1,683−77%

27Chaffee County, COCO20,831+1,567−56%

28Gunnison County, COCO17,439+1,368−63%

29Morgan County, COCO30,306+988−81%

30San Miguel County, COCO7,753+765−74%

31Custer County, COCO5,590+752−52%

32Ouray County, COCO5,265+694−52%

33Gilpin County, COCO6,073+684−59%

34Rio Blanco County, COCO6,683+680+4757%

35Fremont County, COCO50,039+679−95%

36Moffat County, COCO13,122+611−67%

37Bent County, COCO5,716+501−47%

38Alamosa County, COCO16,688+479−64%

39Crowley County, COCO5,677+305−81%

40Las Animas County, COCO14,391+300−79%

41Kit Carson County, COCO7,069+259−70%

42Dolores County, COCO2,466+220−35%

43Yuma County, COCO9,896+202−77%

44Saguache County, COCO6,732+191−85%

45San Juan County, COCO813+141−175%

46Hinsdale County, COCO753+53−84%

47Phillips County, COCO4,420-38−113%

48Washington County, COCO4,732-112−198%

49Mineral County, COCO910-119−144%

50Costilla County, COCO3,679-139−129%

51Conejos County, COCO7,529-144−115%

52Jackson County, COCO1,211-183+554%

53Kiowa County, COCO1,412-224+239%

54Clear Creek County, COCO8,994-234−114%

55Sedgwick County, COCO2,247-368−746%

56Cheyenne County, COCO1,713-395+138%

57Rio Grande County, COCO11,087-431−126%

58Lake County, COCO7,552-502−128%

59Lincoln County, COCO5,645-620−140%

60Baca County, COCO3,347-729+1769%

61Huerfano County, COCO7,011-1,151−162%

62Otero County, COCO17,683-1,480−1275%

63Prowers County, COCO11,884-1,932−270%

SHOWING 1–63 OF 63

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