RANKING · 2025 ESTIMATES · 99 SHOWN OF 99

Most densely populated, Iowa counties

Iowa counties ranked by residents per square mile (2025). This list covers the 99 counties in Iowa that qualify, ranked against each other statewide. The median across all 99 is 26. Biggest climber in the top 100 since 2020: Madison County, IA, up 5 places to #38.

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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, IAIA516,546902+38%

02Scott County, IAIA175,259383+10%

03Linn County, IAIA232,028324+21%

04Johnson County, IAIA160,044261+44%

05Black Hawk County, IAIA131,532232+3%

06▲1Dallas County, IAIA118,457201+191%

07▼1Story County, IAIA101,291177+27%

08Dubuque County, IAIA99,381163+11%

09Woodbury County, IAIA106,649122+3%

10▲3Warren County, IAIA57,331101+41%

11Pottawattamie County, IAIA92,99698+6%

12▼2Muscatine County, IAIA41,853960%

13▼1Des Moines County, IAIA38,07792−10%

14Wapello County, IAIA35,21082−2%

15Cerro Gordo County, IAIA42,37275−9%

16Marshall County, IAIA39,89070+1%

17Clinton County, IAIA46,00266−8%

18Lee County, IAIA32,30662−15%

19Marion County, IAIA34,19262+7%

20Bremer County, IAIA25,29658+8%

21Jasper County, IAIA38,15352+3%

22Webster County, IAIA36,83851−8%

23▲2Sioux County, IAIA36,77448+16%

24▲2Dickinson County, IAIA18,07748+10%

25▼1Boone County, IAIA26,79947+2%

26▼3Henry County, IAIA19,34945−5%

27Washington County, IAIA22,66740+10%

28Mahaska County, IAIA21,88038−2%

29▲4Jones County, IAIA21,25337+5%

30▲1Buchanan County, IAIA20,88337−1%

31▲3Benton County, IAIA26,00436+3%

32▼3Carroll County, IAIA20,30336−5%

33▼3Buena Vista County, IAIA20,449360%

34▼2Jefferson County, IAIA15,29135−6%

35Mills County, IAIA14,79334+2%

36Cedar County, IAIA18,35932+1%

37Poweshiek County, IAIA18,36831−2%

38▲5Madison County, IAIA17,27031+23%

39▲1Delaware County, IAIA17,67431−4%

40▼1Jackson County, IAIA19,28830−5%

41Plymouth County, IAIA25,69730+3%

42▼4Floyd County, IAIA14,90130−12%

43▼1Hardin County, IAIA16,45529−13%

44Winneshiek County, IAIA19,73329−7%

45Clay County, IAIA16,20229−7%

46▲2Iowa County, IAIA16,50428+5%

47▼1Union County, IAIA11,82928−4%

48▼1Page County, IAIA14,85628−12%

49▲1Fayette County, IAIA19,04726−13%

50▼1Louisa County, IAIA10,41626−15%

51▲1Hamilton County, IAIA14,94426−9%

52▼1Winnebago County, IAIA10,25126−13%

53▲1O'Brien County, IAIA14,22025−6%

54▲2Grundy County, IAIA12,361250%

55▼2Appanoose County, IAIA12,07724−12%

56▼1Butler County, IAIA14,04924−8%

57Montgomery County, IAIA10,00224−15%

58▲1Tama County, IAIA16,79623−7%

59▼1Chickasaw County, IAIA11,66323−11%

60Emmet County, IAIA9,10723−17%

61Cass County, IAIA12,96023−12%

62Crawford County, IAIA16,23723−4%

63▲1Mitchell County, IAIA10,65023−2%

64▲3Allamakee County, IAIA14,23822−3%

65▼2Clarke County, IAIA9,57422+5%

66▼1Wright County, IAIA12,80122−11%

67▼1Humboldt County, IAIA9,40922−9%

68Clayton County, IAIA16,84522−10%

69▲1Lyon County, IAIA12,35421+5%

70▼1Harrison County, IAIA14,62321−7%

71▲1Lucas County, IAIA8,84721−6%

72▲1Howard County, IAIA9,41520−5%

73▲1Shelby County, IAIA11,68920−11%

74▼3Cherokee County, IAIA11,36920−13%

75Hancock County, IAIA10,52818−13%

76▲1Davis County, IAIA9,23018+8%

77▼1Worth County, IAIA7,33818−7%

78Guthrie County, IAIA10,78218−5%

79Monroe County, IAIA7,40617−8%

80▲2Franklin County, IAIA9,86817−8%

81Keokuk County, IAIA9,79717−14%

82▼2Calhoun County, IAIA9,56217−14%

83Sac County, IAIA9,52517−17%

84▲1Palo Alto County, IAIA8,89916−12%

85▼1Ida County, IAIA6,77716−14%

86▲1Greene County, IAIA8,65815−16%

87▼1Osceola County, IAIA5,98015−15%

88Kossuth County, IAIA14,32215−17%

89Van Buren County, IAIA7,13115−9%

90Decatur County, IAIA7,65514−12%

91Adair County, IAIA7,40313−10%

92▲3Wayne County, IAIA6,738130%

93▼1Fremont County, IAIA6,52213−19%

94▼1Audubon County, IAIA5,50912−19%

95▼1Monona County, IAIA8,53912−15%

96Pocahontas County, IAIA6,81912−21%

97Taylor County, IAIA5,83511−16%

98▲1Ringgold County, IAIA4,6429−15%

99▼1Adams County, IAIA3,6179−19%

SHOWING 1–99 OF 99

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU POPULATION ESTIMATES