Counties in Iowa by population under 18

Davis County had the highest population under 18 of 99 counties in 2022, at 30.3%. Story County had the lowest, at 16.4%. The median was 22.6% and the figure for Iowa was 22.9%. Source: the U.S. Census Bureau.

Keep it in a collection in your library.
Highest30.3Davis County
Lowest16.4Story County
Median22.699 counties
Iowa22.9History

Map of counties, 2022

Adair County: 22.2 %Adams County: 21.8 %Allamakee County: 23.9 %Appanoose County: 21.3 %Audubon County: 21.7 %Benton County: 23.4 %Black Hawk County: 21.9 %Boone County: 22.1 %Bremer County: 22.9 %Buchanan County: 26 %Buena Vista County: 26.1 %Butler County: 22.2 %Calhoun County: 20.9 %Carroll County: 24 %Cass County: 22.3 %Cedar County: 22.1 %Cerro Gordo County: 20.2 %Cherokee County: 21.7 %Chickasaw County: 22.9 %Clarke County: 25.2 %Clay County: 22.6 %Clayton County: 21.8 %Clinton County: 23 %Crawford County: 26.2 %Dallas County: 26.8 %Davis County: 30.3 %Decatur County: 22.5 %Delaware County: 23.2 %Des Moines County: 21.6 %Dickinson County: 18.9 %Dubuque County: 22.1 %Emmet County: 20.8 %Fayette County: 21.2 %Floyd County: 23.5 %Franklin County: 23.7 %Fremont County: 22.5 %Greene County: 22 %Grundy County: 24 %Guthrie County: 21.5 %Hamilton County: 23.2 %Hancock County: 21.8 %Hardin County: 21.2 %Harrison County: 23.2 %Henry County: 20.5 %Howard County: 24.8 %Humboldt County: 24 %Ida County: 23.3 %Iowa County: 22.7 %Jackson County: 21.6 %Jasper County: 22 %Jefferson County: 18.8 %Johnson County: 19.6 %Jones County: 20.7 %Keokuk County: 23.2 %Kossuth County: 21.6 %Lee County: 21.4 %Linn County: 22.6 %Louisa County: 21.8 %Lucas County: 23.7 %Lyon County: 28.5 %Madison County: 25.2 %Mahaska County: 23.7 %Marion County: 23 %Marshall County: 25.4 %Mills County: 23.7 %Mitchell County: 23.9 %Monona County: 22.2 %Monroe County: 22.8 %Montgomery County: 22 %Muscatine County: 23.5 %O'Brien County: 23.8 %Osceola County: 22.4 %Page County: 19.9 %Palo Alto County: 22.1 %Plymouth County: 24.9 %Pocahontas County: 22.8 %Polk County: 24 %Pottawattamie County: 22.9 %Poweshiek County: 19.3 %Ringgold County: 22.2 %Sac County: 22.1 %Scott County: 23 %Shelby County: 22.1 %Sioux County: 27.5 %Story County: 16.4 %Tama County: 23.9 %Taylor County: 23.7 %Union County: 22 %Van Buren County: 24.4 %Wapello County: 23.7 %Warren County: 25.2 %Washington County: 24.2 %Wayne County: 26.4 %Webster County: 21.2 %Winnebago County: 20.3 %Winneshiek County: 18.9 %Woodbury County: 25.7 %Worth County: 21.9 %Wright County: 25.1 %
  • Under 21
  • 21 to 22
  • 22 to 23
  • 23 to 24
  • 24 and over
%, 2022. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2022

Davis County: 30.3 %Davis County30.3Lyon County: 28.5 %Lyon County28.5Sioux County: 27.5 %Sioux County27.5Dallas County: 26.8 %Dallas County26.8Wayne County: 26.4 %Wayne County26.4Crawford County: 26.2 %Crawford County26.2Buena Vista County: 26.1 %Buena Vista County26.1Buchanan County: 26 %Buchanan County26Woodbury County: 25.7 %Woodbury County25.7Marshall County: 25.4 %Marshall County25.4Clarke County: 25.2 %Clarke County25.2Madison County: 25.2 %Madison County25.2Warren County: 25.2 %Warren County25.2Wright County: 25.1 %Wright County25.1Plymouth County: 24.9 %Plymouth County24.9Howard County: 24.8 %Howard County24.8Van Buren County: 24.4 %Van Buren County24.4Washington County: 24.2 %Washington County24.2Polk County: 24 %Polk County24Carroll County: 24 %Carroll County24Grundy County: 24 %Grundy County24Humboldt County: 24 %Humboldt County24Tama County: 23.9 %Tama County23.9Mitchell County: 23.9 %Mitchell County23.9Allamakee County: 23.9 %Allamakee County23.9O'Brien County: 23.8 %O'Brien County23.8Mahaska County: 23.7 %Mahaska County23.7Wapello County: 23.7 %Wapello County23.7Taylor County: 23.7 %Taylor County23.7Lucas County: 23.7 %Lucas County23.7Mills County: 23.7 %Mills County23.7Franklin County: 23.7 %Franklin County23.7Floyd County: 23.5 %Floyd County23.5Muscatine County: 23.5 %Muscatine County23.5Benton County: 23.4 %Benton County23.4Ida County: 23.3 %Ida County23.3Hamilton County: 23.2 %Hamilton County23.2Keokuk County: 23.2 %Keokuk County23.2Delaware County: 23.2 %Delaware County23.2Harrison County: 23.2 %Harrison County23.2Davis County: 30.3 %Davis County30.3Lyon County: 28.5 %Lyon County28.5Sioux County: 27.5 %Sioux County27.5Dallas County: 26.8 %Dallas County26.8Wayne County: 26.4 %Wayne County26.4Crawford County: 26.2 %Crawford County26.2Buena Vista County: 26.1 %Buena Vista County26.1Buchanan County: 26 %Buchanan County26Woodbury County: 25.7 %Woodbury County25.7Marshall County: 25.4 %Marshall County25.4Clarke County: 25.2 %Clarke County25.2Madison County: 25.2 %Madison County25.2Warren County: 25.2 %Warren County25.2Wright County: 25.1 %Wright County25.1Plymouth County: 24.9 %Plymouth County24.9Howard County: 24.8 %Howard County24.8Van Buren County: 24.4 %Van Buren County24.4Washington County: 24.2 %Washington County24.2Polk County: 24 %Polk County24Carroll County: 24 %Carroll County24Grundy County: 24 %Grundy County24Humboldt County: 24 %Humboldt County24Tama County: 23.9 %Tama County23.9Mitchell County: 23.9 %Mitchell County23.9Allamakee County: 23.9 %Allamakee County23.9O'Brien County: 23.8 %O'Brien County23.8Mahaska County: 23.7 %Mahaska County23.7Wapello County: 23.7 %Wapello County23.7Taylor County: 23.7 %Taylor County23.7Lucas County: 23.7 %Lucas County23.7Mills County: 23.7 %Mills County23.7Franklin County: 23.7 %Franklin County23.7Floyd County: 23.5 %Floyd County23.5Muscatine County: 23.5 %Muscatine County23.5Benton County: 23.4 %Benton County23.4Ida County: 23.3 %Ida County23.3Hamilton County: 23.2 %Hamilton County23.2Keokuk County: 23.2 %Keokuk County23.2Delaware County: 23.2 %Delaware County23.2Harrison County: 23.2 %Harrison County23.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2022 (%)Change on 2021
1Davis County30.3-0.1 pts
2Lyon County28.5-0 pts
3Sioux County27.5-0.2 pts
4Dallas County26.8-0.2 pts
5Wayne County26.4-0.2 pts
6Crawford County26.2-0.2 pts
7Buena Vista County26.1-0.3 pts
8Buchanan County26-0.2 pts
9Woodbury County25.7-0.2 pts
10Marshall County25.4+0.3 pts
11Clarke County25.2+0.2 pts
12Madison County25.2-0 pts
13Warren County25.2-0.2 pts
14Wright County25.1+0.3 pts
15Plymouth County24.9-0.3 pts
16Howard County24.8+0.2 pts
17Van Buren County24.4+0.5 pts
18Washington County24.2-0.1 pts
19Polk County24-0.3 pts
20Carroll County24-0.2 pts
21Grundy County24+0.3 pts
22Humboldt County24+0.1 pts
23Tama County23.90 pts
24Mitchell County23.9-0.1 pts
25Allamakee County23.9+0.3 pts
26O'Brien County23.8+0.5 pts
27Mahaska County23.7-0.1 pts
28Wapello County23.7-0.3 pts
29Taylor County23.7+0.1 pts
30Lucas County23.70 pts
31Mills County23.7-0.3 pts
32Franklin County23.7+0.1 pts
33Floyd County23.5+0.2 pts
34Muscatine County23.5-0.3 pts
35Benton County23.4-0.2 pts
36Ida County23.3-0.2 pts
37Hamilton County23.20 pts
38Keokuk County23.2-0.2 pts
39Delaware County23.2-0.2 pts
40Harrison County23.2-0.2 pts
41Marion County23-0.1 pts
42Clinton County23+0.2 pts
43Scott County23-0.3 pts
44Chickasaw County22.9-0.4 pts
45Bremer County22.9-0 pts
46Pottawattamie County22.9-0.3 pts
47Monroe County22.8-0.5 pts
48Pocahontas County22.8+0.4 pts
49Iowa County22.7-0.2 pts
50Linn County22.6-0.2 pts
51Clay County22.6-0.1 pts
52Decatur County22.5+0.1 pts
53Fremont County22.5+0.1 pts
54Osceola County22.4-0.1 pts
55Cass County22.3+0.3 pts
56Adair County22.2-0.1 pts
57Butler County22.20 pts
58Ringgold County22.2+0.5 pts
59Monona County22.20 pts
60Boone County22.1-0.3 pts
61Cedar County22.1-0.3 pts
62Sac County22.1+0.1 pts
63Palo Alto County22.1-0.3 pts
64Dubuque County22.1-0.2 pts
65Shelby County22.1-0.1 pts
66Montgomery County22-0.1 pts
67Greene County22+0.3 pts
68Jasper County22+0.1 pts
69Union County22-0.4 pts
70Worth County21.90 pts
71Black Hawk County21.9-0 pts
72Clayton County21.8+0.1 pts
73Adams County21.8+0.1 pts
74Louisa County21.8-0.2 pts
75Hancock County21.80 pts
76Audubon County21.7+0.4 pts
77Cherokee County21.7+0.3 pts
78Jackson County21.6-0.1 pts
79Kossuth County21.6+0.3 pts
80Des Moines County21.6-0.1 pts
81Guthrie County21.5+0.2 pts
82Lee County21.4+0.1 pts
83Appanoose County21.3-0.4 pts
84Hardin County21.2-0.5 pts
85Fayette County21.20 pts
86Webster County21.2+0.1 pts
87Calhoun County20.9+0.1 pts
88Emmet County20.8-0.5 pts
89Jones County20.7-0.2 pts
90Henry County20.5-0.2 pts
91Winnebago County20.3-0.4 pts
92Cerro Gordo County20.20 pts
93Page County19.9-0.3 pts
94Johnson County19.6-0.3 pts
95Poweshiek County19.3-0.2 pts
96Dickinson County18.9-0.2 pts
96Winneshiek County18.9-0 pts
98Jefferson County18.8-0.2 pts
99Story County16.4-0.1 pts

Other periods

About this ranking

Residents aged 0 to 17 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.

Uses the US age of majority. Not comparable with population_0_14_share, which stops at 14.

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, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in Iowa by population under 18, 2022) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Iowa by population under 18, 2022. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-under-18/iowa-counties?period=2022. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in Iowa by population under 18, 2022. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-under-18/iowa-counties?period=2022.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Iowa by population under 18, 2022 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/iowa-counties?period=2022 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_iowa_by_2022,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Iowa by population under 18, 2022}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/population-under-18/iowa-counties?period=2022. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Iowa by population under 18, 2022
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/population-under-18/iowa-counties?period=2022
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/iowa-counties?period=2022.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  - 
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Rank Counties in Iowa by population under 18 using official data, and cite the source.
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Questions

Which county has the highest population under 18?

Davis County, with 30.3% in 2022, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Story County, with 16.4% 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, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.

Population under 18: other rankings

Counties in Iowa: more rankings