Data / Rankings / Population under 18 / Counties in Iowa

Counties in Iowa by population under 18

Davis County had the highest population under 18 of 99 counties in 2023, at 29.9%. Story County had the lowest, at 16.3%. The median was 22.4% and the figure for Iowa was 22.7%. Source: the U.S. Census Bureau.

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Highest29.9Davis County
Lowest16.3Story County
Median22.499 counties
Iowa22.7History

Map of counties, 2023

Adair County: 22.4 %Adams County: 21.2 %Allamakee County: 24.1 %Appanoose County: 21.4 %Audubon County: 22 %Benton County: 23.1 %Black Hawk County: 21.8 %Boone County: 21.9 %Bremer County: 22.8 %Buchanan County: 25.8 %Buena Vista County: 25.9 %Butler County: 21.7 %Calhoun County: 21.3 %Carroll County: 23.9 %Cass County: 22.4 %Cedar County: 21.6 %Cerro Gordo County: 20.1 %Cherokee County: 22.3 %Chickasaw County: 22.9 %Clarke County: 24.9 %Clay County: 22.2 %Clayton County: 21.9 %Clinton County: 22.7 %Crawford County: 26.2 %Dallas County: 26.4 %Davis County: 29.9 %Decatur County: 22.9 %Delaware County: 23.1 %Des Moines County: 21.3 %Dickinson County: 18.8 %Dubuque County: 22 %Emmet County: 20.9 %Fayette County: 21.1 %Floyd County: 23.4 %Franklin County: 24 %Fremont County: 22.1 %Greene County: 21.8 %Grundy County: 24.2 %Guthrie County: 21.7 %Hamilton County: 23.4 %Hancock County: 21.7 %Hardin County: 21 %Harrison County: 23.1 %Henry County: 20.7 %Howard County: 24.2 %Humboldt County: 23.6 %Ida County: 23.2 %Iowa County: 22.4 %Jackson County: 21.7 %Jasper County: 21.9 %Jefferson County: 18.1 %Johnson County: 19.4 %Jones County: 20.4 %Keokuk County: 23 %Kossuth County: 21.6 %Lee County: 21.4 %Linn County: 22.4 %Louisa County: 21.4 %Lucas County: 23.8 %Lyon County: 28.1 %Madison County: 24.8 %Mahaska County: 23.6 %Marion County: 22.9 %Marshall County: 25.3 %Mills County: 23.6 %Mitchell County: 23.8 %Monona County: 22 %Monroe County: 22.7 %Montgomery County: 21.8 %Muscatine County: 23.1 %O'Brien County: 23.8 %Osceola County: 21.3 %Page County: 19.8 %Palo Alto County: 22.3 %Plymouth County: 24.7 %Pocahontas County: 22.7 %Polk County: 23.8 %Pottawattamie County: 22.7 %Poweshiek County: 19 %Ringgold County: 21.7 %Sac County: 22.2 %Scott County: 22.7 %Shelby County: 22.4 %Sioux County: 27.3 %Story County: 16.3 %Tama County: 23.8 %Taylor County: 24.1 %Union County: 21.8 %Van Buren County: 24.3 %Wapello County: 23.6 %Warren County: 24.9 %Washington County: 24.1 %Wayne County: 26.3 %Webster County: 21.3 %Winnebago County: 20.3 %Winneshiek County: 18.8 %Woodbury County: 25.5 %Worth County: 22.2 %Wright County: 25.1 %
  • Under 21
  • 21 to 22
  • 22 to 23
  • 23 to 24
  • 24 and over
%, 2023. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2023

Davis County: 29.9 %Davis County29.9Lyon County: 28.1 %Lyon County28.1Sioux County: 27.3 %Sioux County27.3Dallas County: 26.4 %Dallas County26.4Wayne County: 26.3 %Wayne County26.3Crawford County: 26.2 %Crawford County26.2Buena Vista County: 25.9 %Buena Vista County25.9Buchanan County: 25.8 %Buchanan County25.8Woodbury County: 25.5 %Woodbury County25.5Marshall County: 25.3 %Marshall County25.3Wright County: 25.1 %Wright County25.1Clarke County: 24.9 %Clarke County24.9Warren County: 24.9 %Warren County24.9Madison County: 24.8 %Madison County24.8Plymouth County: 24.7 %Plymouth County24.7Van Buren County: 24.3 %Van Buren County24.3Howard County: 24.2 %Howard County24.2Grundy County: 24.2 %Grundy County24.2Washington County: 24.1 %Washington County24.1Allamakee County: 24.1 %Allamakee County24.1Taylor County: 24.1 %Taylor County24.1Franklin County: 24 %Franklin County24Carroll County: 23.9 %Carroll County23.9Lucas County: 23.8 %Lucas County23.8Polk County: 23.8 %Polk County23.8Tama County: 23.8 %Tama County23.8O'Brien County: 23.8 %O'Brien County23.8Mitchell County: 23.8 %Mitchell County23.8Wapello County: 23.6 %Wapello County23.6Humboldt County: 23.6 %Humboldt County23.6Mahaska County: 23.6 %Mahaska County23.6Mills County: 23.6 %Mills County23.6Floyd County: 23.4 %Floyd County23.4Hamilton County: 23.4 %Hamilton County23.4Ida County: 23.2 %Ida County23.2Harrison County: 23.1 %Harrison County23.1Delaware County: 23.1 %Delaware County23.1Benton County: 23.1 %Benton County23.1Muscatine County: 23.1 %Muscatine County23.1Keokuk County: 23 %Keokuk County23Davis County: 29.9 %Davis County29.9Lyon County: 28.1 %Lyon County28.1Sioux County: 27.3 %Sioux County27.3Dallas County: 26.4 %Dallas County26.4Wayne County: 26.3 %Wayne County26.3Crawford County: 26.2 %Crawford County26.2Buena Vista County: 25.9 %Buena Vista County25.9Buchanan County: 25.8 %Buchanan County25.8Woodbury County: 25.5 %Woodbury County25.5Marshall County: 25.3 %Marshall County25.3Wright County: 25.1 %Wright County25.1Clarke County: 24.9 %Clarke County24.9Warren County: 24.9 %Warren County24.9Madison County: 24.8 %Madison County24.8Plymouth County: 24.7 %Plymouth County24.7Van Buren County: 24.3 %Van Buren County24.3Howard County: 24.2 %Howard County24.2Grundy County: 24.2 %Grundy County24.2Washington County: 24.1 %Washington County24.1Allamakee County: 24.1 %Allamakee County24.1Taylor County: 24.1 %Taylor County24.1Franklin County: 24 %Franklin County24Carroll County: 23.9 %Carroll County23.9Lucas County: 23.8 %Lucas County23.8Polk County: 23.8 %Polk County23.8Tama County: 23.8 %Tama County23.8O'Brien County: 23.8 %O'Brien County23.8Mitchell County: 23.8 %Mitchell County23.8Wapello County: 23.6 %Wapello County23.6Humboldt County: 23.6 %Humboldt County23.6Mahaska County: 23.6 %Mahaska County23.6Mills County: 23.6 %Mills County23.6Floyd County: 23.4 %Floyd County23.4Hamilton County: 23.4 %Hamilton County23.4Ida County: 23.2 %Ida County23.2Harrison County: 23.1 %Harrison County23.1Delaware County: 23.1 %Delaware County23.1Benton County: 23.1 %Benton County23.1Muscatine County: 23.1 %Muscatine County23.1Keokuk County: 23 %Keokuk County23
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2023 (%)Change on 2022
1Davis County29.9-0.3 pts
2Lyon County28.1-0.4 pts
3Sioux County27.3-0.2 pts
4Dallas County26.4-0.4 pts
5Wayne County26.3-0.1 pts
6Crawford County26.2-0 pts
7Buena Vista County25.9-0.2 pts
8Buchanan County25.8-0.2 pts
9Woodbury County25.5-0.2 pts
10Marshall County25.3-0.1 pts
11Wright County25.1+0.1 pts
12Clarke County24.9-0.3 pts
13Warren County24.9-0.3 pts
14Madison County24.8-0.4 pts
15Plymouth County24.7-0.1 pts
16Van Buren County24.3-0.1 pts
17Howard County24.2-0.6 pts
18Grundy County24.2+0.2 pts
19Washington County24.1-0 pts
20Allamakee County24.1+0.3 pts
21Taylor County24.1+0.3 pts
22Franklin County24+0.3 pts
23Carroll County23.9-0.1 pts
24Lucas County23.8+0.1 pts
25Polk County23.8-0.2 pts
26Tama County23.8-0.1 pts
27O'Brien County23.8-0 pts
28Mitchell County23.8-0.1 pts
29Wapello County23.6-0.1 pts
30Humboldt County23.6-0.3 pts
31Mahaska County23.6-0.2 pts
32Mills County23.6-0.1 pts
33Floyd County23.4-0.1 pts
34Hamilton County23.4+0.2 pts
35Ida County23.2-0 pts
36Harrison County23.1-0 pts
37Delaware County23.1-0.1 pts
38Benton County23.1-0.3 pts
39Muscatine County23.1-0.4 pts
40Keokuk County23-0.2 pts
41Chickasaw County22.9-0 pts
42Marion County22.9-0.1 pts
43Decatur County22.9+0.3 pts
44Bremer County22.8-0.1 pts
45Scott County22.7-0.3 pts
46Clinton County22.7-0.3 pts
47Pocahontas County22.7-0.1 pts
48Monroe County22.7-0.1 pts
49Pottawattamie County22.7-0.2 pts
50Linn County22.4-0.2 pts
51Cass County22.4+0.1 pts
51Iowa County22.4-0.3 pts
53Adair County22.4+0.1 pts
54Shelby County22.4+0.3 pts
55Cherokee County22.3+0.6 pts
56Palo Alto County22.3+0.2 pts
57Clay County22.2-0.3 pts
58Worth County22.2+0.3 pts
59Sac County22.2+0.1 pts
60Fremont County22.1-0.4 pts
61Monona County22-0.1 pts
62Audubon County22+0.3 pts
63Dubuque County22-0.1 pts
64Jasper County21.9-0.1 pts
65Clayton County21.9+0.1 pts
66Boone County21.9-0.2 pts
67Montgomery County21.8-0.2 pts
68Greene County21.8-0.2 pts
69Black Hawk County21.8-0.1 pts
70Union County21.8-0.2 pts
71Ringgold County21.7-0.5 pts
72Butler County21.7-0.5 pts
73Jackson County21.7+0.1 pts
74Hancock County21.7-0.1 pts
75Guthrie County21.7+0.1 pts
76Cedar County21.6-0.6 pts
77Kossuth County21.6-0.1 pts
78Lee County21.40 pts
79Appanoose County21.4+0.1 pts
80Louisa County21.4-0.4 pts
81Des Moines County21.3-0.2 pts
82Osceola County21.3-1 pts
83Calhoun County21.3+0.4 pts
84Webster County21.3+0.1 pts
85Adams County21.2-0.6 pts
86Fayette County21.1-0.1 pts
87Hardin County21-0.2 pts
88Emmet County20.9+0.1 pts
89Henry County20.7+0.2 pts
90Jones County20.4-0.4 pts
91Winnebago County20.3+0.1 pts
92Cerro Gordo County20.1-0 pts
93Page County19.8-0.1 pts
94Johnson County19.4-0.2 pts
95Poweshiek County19-0.3 pts
96Dickinson County18.8-0.1 pts
97Winneshiek County18.8-0.1 pts
98Jefferson County18.1-0.6 pts
99Story County16.3-0.1 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, 2023) [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, 2023. 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=2023. 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, 2023. 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=2023.

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, 2023 [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=2023 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_iowa_by_2023,
  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, 2023}},
  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=2023. 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, 2023
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=2023
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/iowa-counties?period=2023.
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 29.9% in 2023, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Story County, with 16.3% 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, 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