RANKING · 2010 CENSUS · 99 SHOWN OF 99

Most densely populated, Iowa counties · 2010

Iowa counties ranked by residents per square mile (2010). 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 2000

01Polk County, IAIA516,546752+15%

02Scott County, IAIA175,259361+4%

03Linn County, IAIA232,028295+10%

04Black Hawk County, IAIA131,532232+2%

05Johnson County, IAIA160,044214+18%

06Story County, IAIA101,291156+12%

07Dubuque County, IAIA99,381154+5%

08Woodbury County, IAIA106,649117−2%

09Dallas County, IAIA118,457112+62%

10Pottawattamie County, IAIA92,99698+6%

11Muscatine County, IAIA41,85398+2%

12Des Moines County, IAIA38,07797−5%

13Wapello County, IAIA35,21082−1%

14Warren County, IAIA57,33181+14%

15Cerro Gordo County, IAIA42,37278−5%

16Marshall County, IAIA39,89071+3%

17Clinton County, IAIA46,00271−2%

18Lee County, IAIA32,30669−6%

19Marion County, IAIA34,19260+4%

20Bremer County, IAIA25,29656+4%

21Webster County, IAIA36,83853−6%

22Jasper County, IAIA38,15350−1%

23Henry County, IAIA19,34946−1%

24Boone County, IAIA26,799460%

25Sioux County, IAIA36,77444+7%

26Dickinson County, IAIA18,07744+1%

27Mahaska County, IAIA21,880390%

28Jefferson County, IAIA15,29139+4%

29Washington County, IAIA22,66738+5%

30Buchanan County, IAIA20,88337−1%

31Carroll County, IAIA20,30337−3%

32Benton County, IAIA26,00436+3%

33Jones County, IAIA21,25336+2%

34Buena Vista County, IAIA20,44935−1%

35Mills County, IAIA14,79334+4%

36Floyd County, IAIA14,90133−4%

37Poweshiek County, IAIA18,36832+1%

38Cedar County, IAIA18,35932+2%

39Jackson County, IAIA19,28831−2%

40Hardin County, IAIA16,45531−7%

41Delaware County, IAIA17,67431−3%

42Winneshiek County, IAIA19,73331−1%

43Page County, IAIA14,85630−6%

44Union County, IAIA11,82930+2%

45Clay County, IAIA16,20229−4%

46Plymouth County, IAIA25,69729+1%

47Fayette County, IAIA19,04729−5%

48Louisa County, IAIA10,41628−7%

49Madison County, IAIA17,27028+12%

50Iowa County, IAIA16,50428+4%

51Hamilton County, IAIA14,94427−5%

52Winnebago County, IAIA10,25127−7%

53Emmet County, IAIA9,10726−7%

54Appanoose County, IAIA12,07726−6%

55Butler County, IAIA14,04926−3%

56Montgomery County, IAIA10,00225−9%

57O'Brien County, IAIA14,22025−5%

58Grundy County, IAIA12,36125+1%

59Cass County, IAIA12,96025−5%

60Chickasaw County, IAIA11,66325−5%

61Tama County, IAIA16,79625−2%

62Crawford County, IAIA16,23724+1%

63Clayton County, IAIA16,84523−3%

64Mitchell County, IAIA10,65023−1%

65Wright County, IAIA12,80123−8%

66Humboldt County, IAIA9,40923−5%

67Allamakee County, IAIA14,23822−2%

68Clarke County, IAIA9,57422+2%

69Harrison County, IAIA14,62321−5%

70Cherokee County, IAIA11,36921−7%

71Lucas County, IAIA8,84721−6%

72Shelby County, IAIA11,68921−8%

73Howard County, IAIA9,41520−4%

74Hancock County, IAIA10,52820−6%

75Lyon County, IAIA12,35420−2%

76Worth County, IAIA7,33819−4%

77Guthrie County, IAIA10,78219−4%

78Monroe County, IAIA7,40618−1%

79Franklin County, IAIA9,868180%

80Keokuk County, IAIA9,79718−8%

81Sac County, IAIA9,52518−10%

82Davis County, IAIA9,23017+2%

83Calhoun County, IAIA9,56217−13%

84Palo Alto County, IAIA8,89917−7%

85Ida County, IAIA6,77716−10%

86Greene County, IAIA8,65816−10%

87Osceola County, IAIA5,98016−8%

88Kossuth County, IAIA14,32216−9%

89Decatur County, IAIA7,65516−3%

90Van Buren County, IAIA7,13116−3%

91Fremont County, IAIA6,52215−7%

92Audubon County, IAIA5,50914−10%

93Adair County, IAIA7,40313−7%

94Monona County, IAIA8,53913−8%

95Pocahontas County, IAIA6,81913−16%

96Wayne County, IAIA6,73812−5%

97Taylor County, IAIA5,83512−9%

98Ringgold County, IAIA4,64210−6%

99Adams County, IAIA3,61710−10%

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