RANKING · 2010 CENSUS · 99 SHOWN OF 99

Fastest growing, Iowa counties · 2010

Iowa counties ranked by population growth since the prior decennial census. This list covers the 99 counties in Iowa that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest shrinking Most densely populated Most sparsely populated Best broadband access Worst broadband access

YEAR2000 2010 2020

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01Dallas County, IAIA118,457+62.3%+69%

02Johnson County, IAIA160,044+17.9%+16%

03Polk County, IAIA516,546+15.0%+3%

04Warren County, IAIA57,331+13.7%+6%

05Story County, IAIA101,291+12.0%+55%

06Madison County, IAIA17,270+11.8%−4%

07Linn County, IAIA232,028+10.2%−25%

08Sioux County, IAIA36,774+6.7%+19%

09Pottawattamie County, IAIA92,996+6.2%+1%

10Dubuque County, IAIA99,381+5.1%+60%

11Washington County, IAIA22,667+5.0%−7%

12Iowa County, IAIA16,504+4.4%−39%

13Scott County, IAIA175,259+4.1%−19%

14Jefferson County, IAIA15,291+4.1%−617%

15Bremer County, IAIA25,296+4.1%+82%

16Marion County, IAIA34,192+3.9%−43%

17Mills County, IAIA14,793+3.5%−65%

18Marshall County, IAIA39,890+3.4%+26%

19Benton County, IAIA26,004+3.0%−76%

20Davis County, IAIA9,230+2.5%−10%

21Muscatine County, IAIA41,853+2.5%−46%

22Black Hawk County, IAIA131,532+2.4%−29%

23Jones County, IAIA21,253+2.1%−48%

24Union County, IAIA11,829+1.8%−153%

25Cedar County, IAIA18,359+1.7%−63%

26Clarke County, IAIA9,574+1.7%−84%

27Dickinson County, IAIA18,077+1.5%−85%

28Crawford County, IAIA16,237+0.9%−9%

29Grundy County, IAIA12,361+0.7%−76%

30Plymouth County, IAIA25,697+0.6%−91%

31Poweshiek County, IAIA18,368+0.5%−146%

32Boone County, IAIA26,799+0.3%−92%

33Mahaska County, IAIA21,880+0.2%−95%

34Franklin County, IAIA9,868-0.2%−96%

35Monroe County, IAIA7,406-0.6%−52%

36Buchanan County, IAIA20,883-0.6%−154%

37Buena Vista County, IAIA20,449-0.7%−133%

38Mitchell County, IAIA10,650-0.9%+82%

39Henry County, IAIA19,349-0.9%−116%

40Jasper County, IAIA38,153-1.0%−114%

41Wapello County, IAIA35,210-1.2%−216%

42Winneshiek County, IAIA19,733-1.2%−154%

43Lyon County, IAIA12,354-1.5%−2%

44Woodbury County, IAIA106,649-1.6%−129%

45Tama County, IAIA16,796-1.9%−147%

46Clinton County, IAIA46,002-2.1%+18%

47Jackson County, IAIA19,288-2.2%−227%

48Allamakee County, IAIA14,238-2.4%−140%

49Decatur County, IAIA7,655-2.7%−163%

50Carroll County, IAIA20,303-2.8%+30153%

51Butler County, IAIA14,049-2.9%+6%

52Clayton County, IAIA16,845-2.9%+49%

53Van Buren County, IAIA7,131-3.1%−277%

54Delaware County, IAIA17,674-3.5%−270%

55Guthrie County, IAIA10,782-3.5%−192%

56Floyd County, IAIA14,901-3.5%+281%

57Howard County, IAIA9,415-3.7%−394%

58Worth County, IAIA7,338-3.9%+283%

59Clay County, IAIA16,202-4.1%+235%

60Hamilton County, IAIA14,944-4.7%−304%

61O'Brien County, IAIA14,220-4.7%+111%

62Harrison County, IAIA14,623-4.7%−174%

63Des Moines County, IAIA38,077-4.8%+675%

64Wayne County, IAIA6,738-4.9%+2%

65Cerro Gordo County, IAIA42,372-4.9%+708%

66Cass County, IAIA12,960-5.0%+69%

67Chickasaw County, IAIA11,663-5.0%+233%

68Fayette County, IAIA19,047-5.1%−779%

69Humboldt County, IAIA9,409-5.5%+56%

70Webster County, IAIA36,838-5.5%+1982%

71Lucas County, IAIA8,847-5.6%−243%

72Lee County, IAIA32,306-5.8%+251%

73Appanoose County, IAIA12,077-6.1%+3697%

74Page County, IAIA14,856-6.1%−1079%

75Ringgold County, IAIA4,642-6.2%−784%

76Hancock County, IAIA10,528-6.3%+47%

77Louisa County, IAIA10,416-6.5%−228%

78Emmet County, IAIA9,107-6.6%+40%

79Hardin County, IAIA16,455-6.8%+360%

80Adair County, IAIA7,403-6.8%+245%

81Fremont County, IAIA6,522-7.1%+171%

82Palo Alto County, IAIA8,899-7.2%+46%

83Winnebago County, IAIA10,251-7.3%+122%

84Cherokee County, IAIA11,369-7.4%−2%

85Shelby County, IAIA11,689-7.6%+1673%

86Wright County, IAIA12,801-7.7%−1792%

87Osceola County, IAIA5,980-7.7%+113%

88Monona County, IAIA8,539-7.8%+5458%

89Keokuk County, IAIA9,797-7.8%+305%

90Montgomery County, IAIA10,002-8.8%+247%

91Taylor County, IAIA5,835-9.2%+320%

92Kossuth County, IAIA14,322-9.4%+23%

93Ida County, IAIA6,777-9.5%+51%

94Greene County, IAIA8,658-9.9%−411%

95Adams County, IAIA3,617-10.1%+28%

96Sac County, IAIA9,525-10.2%+59%

97Audubon County, IAIA5,509-10.4%+51%

98Calhoun County, IAIA9,562-13.0%+281%

99Pocahontas County, IAIA6,819-15.6%+72%

SHOWING 1–99 OF 99

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