RANKING · 2000 CENSUS · 99 SHOWN OF 99

Most population gained, Iowa counties · 2000

Iowa counties that added the most residents from the 1990 census to 2000, by raw count of people rather than percentage. This list covers the 99 counties in Iowa that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS –

01Polk County, IAIA516,546+47,461–

02Linn County, IAIA232,028+22,934–

03Johnson County, IAIA160,044+14,887–

04Dallas County, IAIA118,457+10,995–

05Scott County, IAIA175,259+7,689–

06Story County, IAIA101,291+5,729–

07Woodbury County, IAIA106,649+5,601–

08Pottawattamie County, IAIA92,996+5,076–

09Warren County, IAIA57,331+4,638–

10Black Hawk County, IAIA131,532+4,214–

11Benton County, IAIA26,004+2,879–

12Dubuque County, IAIA99,381+2,740–

13Jasper County, IAIA38,153+2,418–

14Marion County, IAIA34,192+2,051–

15Muscatine County, IAIA41,853+1,815–

16Sioux County, IAIA36,774+1,686–

17Madison County, IAIA17,270+1,536–

18Dickinson County, IAIA18,077+1,515–

19Plymouth County, IAIA25,697+1,461–

20Mills County, IAIA14,793+1,345–

21Henry County, IAIA19,349+1,110–

22Washington County, IAIA22,667+1,058–

23Iowa County, IAIA16,504+1,041–

24Boone County, IAIA26,799+1,038–

25Marshall County, IAIA39,890+1,035–

26Harrison County, IAIA14,623+936–

27Clarke County, IAIA9,574+846–

28Allamakee County, IAIA14,238+820–

29Mahaska County, IAIA21,880+813–

30Cedar County, IAIA18,359+806–

31Jones County, IAIA21,253+777–

32Tama County, IAIA16,796+684–

33Louisa County, IAIA10,416+591–

34Bremer County, IAIA25,296+512–

35Winneshiek County, IAIA19,733+463–

36Buena Vista County, IAIA20,449+446–

37Guthrie County, IAIA10,782+418–

38Delaware County, IAIA17,674+369–

39Hamilton County, IAIA14,944+367–

40Wapello County, IAIA35,210+364–

41Lucas County, IAIA8,847+352–

42Decatur County, IAIA7,655+351–

43Jackson County, IAIA19,288+346–

44Grundy County, IAIA12,361+340–

45Greene County, IAIA8,658+321–

46Buchanan County, IAIA20,883+249–

47Davis County, IAIA9,230+229–

48Crawford County, IAIA16,237+167–

49Fayette County, IAIA19,047+165–

50Van Buren County, IAIA7,131+133–

51Howard County, IAIA9,415+123–

52Page County, IAIA14,856+106–

53Wright County, IAIA12,801+65–

54Ringgold County, IAIA4,642+49–

55Carroll County, IAIA20,303-2–

56Monona County, IAIA8,539-14–

57Appanoose County, IAIA12,077-22–

58Mitchell County, IAIA10,650-54–

59Shelby County, IAIA11,689-57–

60Worth County, IAIA7,338-82–

61Monroe County, IAIA7,406-98–

62Webster County, IAIA36,838-107–

63Jefferson County, IAIA15,291-129–

64Taylor County, IAIA5,835-156–

65Floyd County, IAIA14,901-158–

66Adair County, IAIA7,403-166–

67Lyon County, IAIA12,354-189–

68Chickasaw County, IAIA11,663-200–

69Clay County, IAIA16,202-213–

70Fremont County, IAIA6,522-216–

71Poweshiek County, IAIA18,368-218–

72Keokuk County, IAIA9,797-224–

73Des Moines County, IAIA38,077-263–

74Osceola County, IAIA5,980-264–

75Hardin County, IAIA16,455-282–

76Cerro Gordo County, IAIA42,372-286–

77Montgomery County, IAIA10,002-305–

78Wayne County, IAIA6,738-337–

79O'Brien County, IAIA14,220-342–

80Humboldt County, IAIA9,409-375–

81Clayton County, IAIA16,845-376–

82Adams County, IAIA3,617-384–

83Calhoun County, IAIA9,562-393–

84Winnebago County, IAIA10,251-399–

85Butler County, IAIA14,049-426–

86Union County, IAIA11,829-441–

87Cass County, IAIA12,960-444–

88Audubon County, IAIA5,509-504–

89Palo Alto County, IAIA8,899-522–

90Ida County, IAIA6,777-528–

91Hancock County, IAIA10,528-538–

92Emmet County, IAIA9,107-542–

93Lee County, IAIA32,306-635–

94Franklin County, IAIA9,868-660–

95Sac County, IAIA9,525-795–

96Pocahontas County, IAIA6,819-863–

97Clinton County, IAIA46,002-891–

98Cherokee County, IAIA11,369-1,063–

99Kossuth County, IAIA14,322-1,428–

SHOWING 1–99 OF 99

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