Data / Rankings / Population density / Counties in Iowa

Counties in Iowa by population density

Polk County had the highest population density of 99 counties in 2022, at 337.9 inhabitants per km². Adams County had the lowest, at 3.3 inhabitants per km². The median was 10.2 inhabitants per km² and the figure for Iowa was 22.1 inhabitants per km². Source: the U.S. Census Bureau.

Highest337.9Polk County
Lowest3.3Adams County
Median10.299 counties
Iowa22.1History

Top 40 counties, 2022

CSVChart (SVG)

Polk CountyPolk County: 337.9 inhabitants per km²337.9Scott CountyScott County: 146.5 inhabitants per km²146.5Linn CountyLinn County: 123.2 inhabitants per km²123.2Johnson CountyJohnson County: 98.7 inhabitants per km²98.7Black Hawk CountyBlack Hawk County: 88.7 inhabitants per km²88.7Dallas CountyDallas County: 70.9 inhabitants per km²70.9Story CountyStory County: 67.3 inhabitants per km²67.3Dubuque CountyDubuque County: 62.7 inhabitants per km²62.7Woodbury CountyWoodbury County: 46.8 inhabitants per km²46.8Pottawattamie CountyPottawattamie County: 37.8 inhabitants per km²37.8Muscatine CountyMuscatine County: 37.5 inhabitants per km²37.5Warren CountyWarren County: 36.8 inhabitants per km²36.8Des Moines CountyDes Moines County: 35.5 inhabitants per km²35.5Wapello CountyWapello County: 31.4 inhabitants per km²31.4Cerro Gordo CountyCerro Gordo County: 28.8 inhabitants per km²28.8Marshall CountyMarshall County: 26.9 inhabitants per km²26.9Clinton CountyClinton County: 25.7 inhabitants per km²25.7Lee CountyLee County: 24.5 inhabitants per km²24.5Marion CountyMarion County: 23.4 inhabitants per km²23.4Bremer CountyBremer County: 22.4 inhabitants per km²22.4Jasper CountyJasper County: 20.1 inhabitants per km²20.1Webster CountyWebster County: 19.8 inhabitants per km²19.8Dickinson CountyDickinson County: 18.3 inhabitants per km²18.3Sioux CountySioux County: 18.2 inhabitants per km²18.2Henry CountyHenry County: 18 inhabitants per km²18Boone CountyBoone County: 18 inhabitants per km²18Washington CountyWashington County: 15.3 inhabitants per km²15.3Mahaska CountyMahaska County: 14.8 inhabitants per km²14.8Jones CountyJones County: 14.1 inhabitants per km²14.1Buchanan CountyBuchanan County: 14 inhabitants per km²14Carroll CountyCarroll County: 13.9 inhabitants per km²13.9Benton CountyBenton County: 13.9 inhabitants per km²13.9Buena Vista CountyBuena Vista County: 13.9 inhabitants per km²13.9Jefferson CountyJefferson County: 13.8 inhabitants per km²13.8Mills CountyMills County: 12.8 inhabitants per km²12.8Poweshiek CountyPoweshiek County: 12.2 inhabitants per km²12.2Cedar CountyCedar County: 12.2 inhabitants per km²12.2Floyd CountyFloyd County: 11.8 inhabitants per km²11.8Delaware CountyDelaware County: 11.8 inhabitants per km²11.8Madison CountyMadison 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

RankCounties2022
inhabitants per km²		Change on 2021
1Polk County337.9+0.6%
2Scott County146.5-0.2%
3Linn County123.2-0.3%
4Johnson County98.7+1%
5Black Hawk County88.7-0.5%
6Dallas County70.9+3.7%
7Story County67.3+0.2%
8Dubuque County62.7-0.2%
9Woodbury County46.8-0.1%
10Pottawattamie County37.8-0.3%
11Muscatine County37.5-0.5%
12Warren County36.8+1.6%
13Des Moines County35.5-0.8%
14Wapello County31.4-0.6%
15Cerro Gordo County28.8-0.9%
16Marshall County26.9-0.2%
17Clinton County25.7-0.5%
18Lee County24.5-1.4%
19Marion County23.4+0.4%
20Bremer County22.4+0.5%
21Jasper County20.1+0.1%
22Webster County19.8-1.3%
23Dickinson County18.3+1%
24Sioux County18.2+0.8%
25Henry County18-0.6%
26Boone County18-0.8%
27Washington County15.3+0.1%
28Mahaska County14.8-0.1%
29Jones County14.1+0.6%
30Buchanan County14-0.1%
31Carroll County13.9-0.9%
32Benton County13.90%
33Buena Vista County13.9-0.7%
34Jefferson County13.8-1.4%
35Mills County12.8+0.5%
36Poweshiek County12.2-0.4%
37Cedar County12.2-0.6%
38Floyd County11.8-0.9%
39Delaware County11.8+0.2%
40Madison County11.7+1.5%
41Jackson County11.7-0.3%
42Plymouth County11.5-0.1%
43Hardin County11.3-0.3%
44Clay County11.2+0.3%
45Winneshiek County11.1-0.2%
46Page County10.9-0.4%
47Iowa County10.9-0.6%
48Union County10.8-1.2%
49Winnebago County10.3+0.1%
50Louisa County10.2-0.9%
51Fayette County10.2-0%
52Hamilton County100%
53Grundy County9.50%
54O'Brien County9.5+0.3%
55Butler County9.5-0.7%
56Appanoose County9.4-1.1%
57Montgomery County9.3-1.1%
58Tama County9.1+0.3%
59Chickasaw County9-1.1%
60Cass County9+0.3%
61Emmet County9-1.3%
62Crawford County8.7-0.6%
63Mitchell County8.7-0.1%
64Clarke County8.7-0.7%
65Allamakee County8.5+0.9%
66Wright County8.5-0.5%
67Humboldt County8.5-1%
68Clayton County8.5-0%
69Harrison County8.1-0.4%
70Lyon County8+1.2%
71Lucas County7.8+0.2%
72Howard County7.8-0.1%
73Cherokee County7.7-0.4%
74Shelby County7.7-0.4%
75Hancock County7.2-0.3%
76Worth County7.1-0.7%
77Davis County7-0.1%
78Guthrie County7+0.8%
79Monroe County6.7-0.8%
80Calhoun County6.6-1.7%
81Keokuk County6.6-0.2%
82Franklin County6.6-0.2%
83Sac County6.5-0.9%
84Ida County6.2-1.2%
85Palo Alto County6-1.7%
86Greene County5.9-0.3%
87Osceola County5.9-1.7%
88Van Buren County5.8-0.1%
89Kossuth County5.8-0.2%
90Decatur County5.7+0.1%
91Adair County5.1-0.8%
92Fremont County4.9-1.8%
93Audubon County4.9-1.3%
94Wayne County4.8-0.8%
95Monona County4.7-1%
96Pocahontas County4.7+0.5%
97Taylor County4.3-0.1%
98Ringgold County3.4+1%
99Adams County3.3-1.1%

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 337.9 inhabitants per km² in 2022, according to the U.S. Census Bureau.

Which county has the lowest population density?

Adams County, with 3.3 inhabitants per km² in 2022.

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