Data / Rankings / Population density / Counties in Iowa

Counties in Iowa by population density

Polk County had the highest population density of 99 counties in 2023, at 341.7 inhabitants per km². Adams County had the lowest, at 3.2 inhabitants per km². The median was 10.2 inhabitants per km² and the figure for Iowa was 22.2 inhabitants per km². Source: the U.S. Census Bureau.

Highest341.7Polk County
Lowest3.2Adams County
Median10.299 counties
Iowa22.2History

Top 40 counties, 2023

CSVChart (SVG)

Polk CountyPolk County: 341.7 inhabitants per km²341.7Scott CountyScott County: 146.8 inhabitants per km²146.8Linn CountyLinn County: 123.2 inhabitants per km²123.2Johnson CountyJohnson County: 99.3 inhabitants per km²99.3Black Hawk CountyBlack Hawk County: 89.3 inhabitants per km²89.3Dallas CountyDallas County: 73.1 inhabitants per km²73.1Story CountyStory County: 68.1 inhabitants per km²68.1Dubuque CountyDubuque County: 62.8 inhabitants per km²62.8Woodbury CountyWoodbury County: 47.1 inhabitants per km²47.1Pottawattamie CountyPottawattamie County: 37.9 inhabitants per km²37.9Warren CountyWarren County: 37.5 inhabitants per km²37.5Muscatine CountyMuscatine County: 37.3 inhabitants per km²37.3Des Moines CountyDes Moines County: 35.5 inhabitants per km²35.5Wapello CountyWapello County: 31.6 inhabitants per km²31.6Cerro Gordo CountyCerro Gordo County: 28.8 inhabitants per km²28.8Marshall CountyMarshall County: 27 inhabitants per km²27Clinton CountyClinton County: 25.6 inhabitants per km²25.6Lee CountyLee County: 24.2 inhabitants per km²24.2Marion CountyMarion County: 23.4 inhabitants per km²23.4Bremer CountyBremer County: 22.5 inhabitants per km²22.5Jasper CountyJasper County: 20.1 inhabitants per km²20.1Webster CountyWebster County: 19.8 inhabitants per km²19.8Sioux CountySioux County: 18.3 inhabitants per km²18.3Dickinson CountyDickinson County: 18.3 inhabitants per km²18.3Boone CountyBoone County: 18 inhabitants per km²18Henry CountyHenry County: 17.4 inhabitants per km²17.4Washington CountyWashington County: 15.3 inhabitants per km²15.3Mahaska CountyMahaska County: 14.8 inhabitants per km²14.8Jones CountyJones County: 14 inhabitants per km²14Buchanan 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: 13.7 inhabitants per km²13.7Mills CountyMills County: 12.9 inhabitants per km²12.9Poweshiek 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: 11.7 inhabitants per km²11.7Jackson CountyJackson 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

RankCounties2023
inhabitants per km²		Change on 2022
1Polk County341.7+1.1%
2Scott County146.8+0.2%
3Linn County123.2-0%
4Johnson County99.3+0.7%
5Black Hawk County89.3+0.7%
6Dallas County73.1+3%
7Story County68.1+1.2%
8Dubuque County62.8+0.2%
9Woodbury County47.1+0.8%
10Pottawattamie County37.9+0.2%
11Warren County37.5+1.8%
12Muscatine County37.3-0.5%
13Des Moines County35.5+0.2%
14Wapello County31.6+0.8%
15Cerro Gordo County28.8+0.1%
16Marshall County27+0.6%
17Clinton County25.6-0.3%
18Lee County24.2-0.9%
19Marion County23.4+0.2%
20Bremer County22.5+0.3%
21Jasper County20.1+0.1%
22Webster County19.8-0.1%
23Sioux County18.3+0.7%
24Dickinson County18.3+0.1%
25Boone County180%
26Henry County17.4-3.4%
27Washington County15.3+0.1%
28Mahaska County14.80%
29Jones County14-0.2%
30Buchanan County14+0.1%
31Carroll County13.9-0.2%
32Benton County13.9+0.1%
33Buena Vista County13.9+0.2%
34Jefferson County13.7-0.7%
35Mills County12.9+0.4%
36Poweshiek County12.2-0.3%
37Cedar County12.2-0.2%
38Floyd County11.8-0.1%
39Delaware County11.7-0.1%
40Jackson County11.7+0.1%
41Madison County11.7-0.3%
42Plymouth County11.50%
43Clay County11.3+0.1%
44Hardin County11.2-0.9%
45Winneshiek County11-1%
46Union County10.8-0.1%
47Page County10.8-1.1%
48Iowa County10.8-0.5%
49Fayette County10.2-0.4%
50Winnebago County10.2-1.1%
51Louisa County10.1-1.1%
52Hamilton County10+0.2%
53Grundy County9.5+0.1%
54O'Brien County9.5-0.3%
55Butler County9.4-0.5%
56Appanoose County9.4-0.1%
57Montgomery County9.2-0.5%
58Emmet County9.1+1%
59Tama County9-0.6%
60Cass County9-0%
61Chickasaw County9-0.4%
62Crawford County8.7-0.1%
63Mitchell County8.7-0.1%
64Clarke County8.6-0.4%
65Allamakee County8.6+0.5%
66Wright County8.5+0.6%
67Humboldt County8.5-0.2%
68Clayton County8.4-0.2%
69Harrison County8.1+0.2%
70Lyon County8.1+1.1%
71Lucas County7.9+0.5%
72Cherokee County7.8+0.9%
73Shelby County7.7+0.6%
74Howard County7.7-1.1%
75Hancock County7.2-0.2%
76Worth County7.10%
77Davis County7+0.2%
78Guthrie County7+0.6%
79Monroe County6.7-0.5%
80Calhoun County6.6+0.5%
80Keokuk County6.6+0.5%
82Franklin County6.6-0.4%
83Sac County6.5+0.2%
84Ida County6.1-1%
85Palo Alto County6.1+0.7%
86Greene County5.8-1.2%
87Osceola County5.8-0.9%
88Van Buren County5.8-0%
89Kossuth County5.7-0.3%
90Decatur County5.6-0.4%
91Adair County5-0.7%
92Fremont County4.9-0.2%
93Audubon County4.8-0.7%
94Wayne County4.8+1.2%
95Monona County4.8+0.1%
96Pocahontas County4.7-1.2%
97Taylor County4.3+1%
98Ringgold County3.4-0.3%
99Adams County3.2-1.2%

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 341.7 inhabitants per km² in 2023, according to the U.S. Census Bureau.

Which county has the lowest population density?

Adams County, with 3.2 inhabitants per km² in 2023.

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