Data / Rankings / Population density / Counties in Iowa

Counties in Iowa by population density

Polk County had the highest population density of 99 counties in 2020, at 332.4 inhabitants per km². Ringgold County had the lowest, at 3.3 inhabitants per km². The median was 10.3 inhabitants per km² and the figure for Iowa was 22.1 inhabitants per km². Source: the U.S. Census Bureau.

Highest332.4Polk County
Lowest3.3Ringgold County
Median10.399 counties
Iowa22.1History

Top 40 counties, 2020

CSVChart (SVG)

Polk CountyPolk County: 332.4 inhabitants per km²332.4Scott CountyScott County: 147.2 inhabitants per km²147.2Linn CountyLinn County: 124.1 inhabitants per km²124.1Johnson CountyJohnson County: 96.4 inhabitants per km²96.4Black Hawk CountyBlack Hawk County: 89.4 inhabitants per km²89.4Story CountyStory County: 66.5 inhabitants per km²66.5Dallas CountyDallas County: 66 inhabitants per km²66Dubuque CountyDubuque County: 63 inhabitants per km²63Woodbury CountyWoodbury County: 46.9 inhabitants per km²46.9Muscatine CountyMuscatine County: 38.1 inhabitants per km²38.1Pottawattamie CountyPottawattamie County: 38 inhabitants per km²38Des Moines CountyDes Moines County: 36 inhabitants per km²36Warren CountyWarren County: 35.6 inhabitants per km²35.6Wapello CountyWapello County: 31.6 inhabitants per km²31.6Cerro Gordo CountyCerro Gordo County: 29.2 inhabitants per km²29.2Marshall CountyMarshall County: 27 inhabitants per km²27Clinton CountyClinton County: 25.8 inhabitants per km²25.8Lee CountyLee County: 25 inhabitants per km²25Marion CountyMarion County: 23.3 inhabitants per km²23.3Bremer CountyBremer County: 22.2 inhabitants per km²22.2Jasper CountyJasper County: 20 inhabitants per km²20Webster CountyWebster County: 20 inhabitants per km²20Henry CountyHenry County: 18.2 inhabitants per km²18.2Boone CountyBoone County: 18.1 inhabitants per km²18.1Sioux CountySioux County: 18 inhabitants per km²18Dickinson CountyDickinson County: 18 inhabitants per km²18Washington CountyWashington County: 15.3 inhabitants per km²15.3Mahaska CountyMahaska County: 15 inhabitants per km²15Carroll CountyCarroll County: 14.1 inhabitants per km²14.1Buena Vista CountyBuena Vista County: 14 inhabitants per km²14Buchanan CountyBuchanan County: 13.9 inhabitants per km²13.9Jefferson CountyJefferson County: 13.9 inhabitants per km²13.9Jones CountyJones County: 13.9 inhabitants per km²13.9Benton CountyBenton County: 13.8 inhabitants per km²13.8Mills CountyMills County: 12.7 inhabitants per km²12.7Cedar CountyCedar County: 12.3 inhabitants per km²12.3Poweshiek CountyPoweshiek County: 12.3 inhabitants per km²12.3Floyd CountyFloyd County: 12 inhabitants per km²12Jackson CountyJackson County: 11.8 inhabitants per km²11.8Delaware CountyDelaware County: 11.7 inhabitants per km²11.7
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2020
inhabitants per km²
1Polk County332.4
2Scott County147.2
3Linn County124.1
4Johnson County96.4
5Black Hawk County89.4
6Story County66.5
7Dallas County66
8Dubuque County63
9Woodbury County46.9
10Muscatine County38.1
11Pottawattamie County38
12Des Moines County36
13Warren County35.6
14Wapello County31.6
15Cerro Gordo County29.2
16Marshall County27
17Clinton County25.8
18Lee County25
19Marion County23.3
20Bremer County22.2
21Jasper County20
22Webster County20
23Henry County18.2
24Boone County18.1
25Sioux County18
26Dickinson County18
27Washington County15.3
28Mahaska County15
29Carroll County14.1
30Buena Vista County14
31Buchanan County13.9
32Jefferson County13.9
33Jones County13.9
34Benton County13.8
35Mills County12.7
36Cedar County12.3
37Poweshiek County12.3
38Floyd County12
39Jackson County11.8
40Delaware County11.7
41Plymouth County11.5
42Madison County11.4
43Hardin County11.4
44Winneshiek County11.2
45Clay County11.1
46Union County11.1
47Iowa County11
47Page County11
49Louisa County10.4
50Fayette County10.3
51Winnebago County10.3
52Hamilton County10.1
53Butler County9.5
54O'Brien County9.5
55Appanoose County9.5
56Grundy County9.5
57Montgomery County9.4
58Chickasaw County9.2
59Tama County9.1
60Emmet County9.1
61Cass County9
62Crawford County8.9
63Clarke County8.7
64Mitchell County8.7
65Wright County8.6
66Humboldt County8.5
67Allamakee County8.5
68Clayton County8.4
69Harrison County8.1
70Lyon County7.8
71Cherokee County7.8
72Howard County7.7
73Lucas County7.7
74Shelby County7.7
75Hancock County7.3
76Worth County7.2
77Davis County7
78Guthrie County6.9
79Monroe County6.8
80Calhoun County6.7
81Keokuk County6.7
82Franklin County6.6
83Sac County6.6
84Ida County6.3
85Palo Alto County6.2
86Osceola County6
87Greene County5.9
88Kossuth County5.9
89Van Buren County5.8
90Decatur County5.6
91Adair County5.1
92Fremont County5
93Audubon County5
94Monona County4.9
95Wayne County4.8
96Pocahontas County4.7
97Taylor County4.3
98Adams County3.4
99Ringgold County3.3

Other periods

About this ranking

Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.

United States: Census Bureau population estimates for 1 July divided by land area (water excluded) from the latest Census Gazetteer files. US tables often give people per square mile; multiply persons per km² by 2.59 to compare.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-09.

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Questions

Which county has the highest population density?

Polk County, with 332.4 inhabitants per km² in 2020, according to the U.S. Census Bureau.

Which county has the lowest population density?

Ringgold County, with 3.3 inhabitants per km² in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². Retrieved 2026-10-09.

Population density: other rankings

Counties in Iowa: more rankings