RANKING · 1990 CENSUS · 99 SHOWN OF 99

Most densely populated, Iowa counties · 1990

Iowa counties ranked by residents per square mile (1990). This list covers the 99 counties in Iowa that qualify, ranked against each other statewide. The median across all 99 is 28.

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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 –

01Polk County, IAIA516,546572–

02Scott County, IAIA175,259330–

03Linn County, IAIA232,028235–

04Black Hawk County, IAIA131,532219–

05Johnson County, IAIA160,044157–

06Dubuque County, IAIA99,381142–

07Story County, IAIA101,291130–

08Woodbury County, IAIA106,649113–

09Des Moines County, IAIA38,077102–

10Muscatine County, IAIA41,85391–

11Pottawattamie County, IAIA92,99687–

12Wapello County, IAIA35,21083–

13Cerro Gordo County, IAIA42,37282–

14Lee County, IAIA32,30675–

15Clinton County, IAIA46,00273–

16Marshall County, IAIA39,89067–

17Warren County, IAIA57,33163–

18Webster County, IAIA36,83856–

19Marion County, IAIA34,19254–

20Bremer County, IAIA25,29652–

21Dallas County, IAIA118,45751–

22Jasper County, IAIA38,15348–

23Henry County, IAIA19,34944–

24Boone County, IAIA26,79944–

25Dickinson County, IAIA18,07739–

26Sioux County, IAIA36,77439–

27Mahaska County, IAIA21,88038–

28Carroll County, IAIA20,30338–

29Jefferson County, IAIA15,29137–

30Buchanan County, IAIA20,88336–

31Buena Vista County, IAIA20,44935–

32Washington County, IAIA22,66734–

33Floyd County, IAIA14,90134–

34Jones County, IAIA21,25334–

35Hardin County, IAIA16,45534–

36Poweshiek County, IAIA18,36833–

37Page County, IAIA14,85632–

38Jackson County, IAIA19,28831–

39Benton County, IAIA26,00431–

40Delaware County, IAIA17,67431–

41Clay County, IAIA16,20231–

42Winnebago County, IAIA10,25130–

43Winneshiek County, IAIA19,73330–

44Mills County, IAIA14,79330–

45Union County, IAIA11,82930–

46Cedar County, IAIA18,35930–

47Fayette County, IAIA19,04730–

48Emmet County, IAIA9,10729–

49Louisa County, IAIA10,41629–

50Montgomery County, IAIA10,00228–

51Hamilton County, IAIA14,94428–

52Appanoose County, IAIA12,07728–

53Butler County, IAIA14,04927–

54Plymouth County, IAIA25,69727–

55O'Brien County, IAIA14,22027–

56Cass County, IAIA12,96027–

57Chickasaw County, IAIA11,66326–

58Iowa County, IAIA16,50425–

59Humboldt County, IAIA9,40925–

60Wright County, IAIA12,80125–

61Clayton County, IAIA16,84524–

62Cherokee County, IAIA11,36924–

63Tama County, IAIA16,79624–

64Grundy County, IAIA12,36124–

65Crawford County, IAIA16,23723–

66Mitchell County, IAIA10,65023–

67Shelby County, IAIA11,68922–

68Madison County, IAIA17,27022–

69Hancock County, IAIA10,52822–

70Allamakee County, IAIA14,23822–

71Sac County, IAIA9,52521–

72Harrison County, IAIA14,62321–

73Lucas County, IAIA8,84721–

74Howard County, IAIA9,41521–

75Lyon County, IAIA12,35420–

76Calhoun County, IAIA9,56220–

77Keokuk County, IAIA9,79720–

78Worth County, IAIA7,33820–

79Franklin County, IAIA9,86820–

80Ida County, IAIA6,77719–

81Clarke County, IAIA9,57419–

82Kossuth County, IAIA14,32219–

83Palo Alto County, IAIA8,89919–

84Monroe County, IAIA7,40619–

85Guthrie County, IAIA10,78219–

86Osceola County, IAIA5,98018–

87Greene County, IAIA8,65818–

88Audubon County, IAIA5,50917–

89Davis County, IAIA9,23017–

90Pocahontas County, IAIA6,81917–

91Fremont County, IAIA6,52216–

92Van Buren County, IAIA7,13116–

93Decatur County, IAIA7,65516–

94Adair County, IAIA7,40315–

95Monona County, IAIA8,53914–

96Wayne County, IAIA6,73813–

97Taylor County, IAIA5,83513–

98Adams County, IAIA3,61711–

99Ringgold County, IAIA4,64210–

SHOWING 1–99 OF 99

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