# Counties in Iowa by population under 18, 2025

All 99 values come from U.S. Census Bureau for 2025, so the places are comparable.

- Indicator id: `population_0_17_share`
- Unit: %
- Definition: 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.
- Source: 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: 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.
- Web page: https://invokely.ai/rankings/population-under-18/iowa-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Davis County | 30 |
| 2 | Lyon County | 26.8 |
| 3 | Sioux County | 26.5 |
| 4 | Wayne County | 26.4 |
| 5 | Buchanan County | 25.5 |
| 6 | Dallas County | 25.5 |
| 7 | Crawford County | 25.4 |
| 8 | Buena Vista County | 25.3 |
| 9 | Woodbury County | 24.9 |
| 10 | Marshall County | 24.7 |
| 11 | Wright County | 24.6 |
| 12 | Plymouth County | 24.4 |
| 13 | Lucas County | 24.2 |
| 14 | Clarke County | 24.1 |
| 15 | Washington County | 24.1 |
| 16 | Madison County | 24 |
| 17 | Howard County | 24 |
| 18 | Warren County | 24 |
| 19 | O'Brien County | 23.8 |
| 20 | Franklin County | 23.8 |
| 21 | Van Buren County | 23.7 |
| 22 | Grundy County | 23.7 |
| 23 | Allamakee County | 23.7 |
| 24 | Hamilton County | 23.7 |
| 25 | Mitchell County | 23.5 |
| 26 | Tama County | 23.4 |
| 27 | Polk County | 23.3 |
| 28 | Carroll County | 23.3 |
| 29 | Mills County | 23 |
| 30 | Taylor County | 23 |
| 31 | Wapello County | 23 |
| 32 | Mahaska County | 23 |
| 33 | Humboldt County | 22.9 |
| 34 | Benton County | 22.8 |
| 35 | Floyd County | 22.7 |
| 36 | Keokuk County | 22.7 |
| 37 | Harrison County | 22.6 |
| 38 | Ida County | 22.6 |
| 39 | Chickasaw County | 22.6 |
| 40 | Cherokee County | 22.6 |
| 41 | Delaware County | 22.6 |
| 42 | Palo Alto County | 22.5 |
| 43 | Monroe County | 22.5 |
| 44 | Clinton County | 22.4 |
| 45 | Muscatine County | 22.4 |
| 46 | Shelby County | 22.3 |
| 47 | Marion County | 22.2 |
| 48 | Pocahontas County | 22.2 |
| 49 | Iowa County | 22.1 |
| 50 | Bremer County | 22.1 |
| 51 | Worth County | 22.1 |
| 52 | Cass County | 22.1 |
| 53 | Scott County | 22 |
| 54 | Sac County | 22 |
| 55 | Audubon County | 22 |
| 56 | Decatur County | 22 |
| 57 | Linn County | 21.9 |
| 58 | Pottawattamie County | 21.8 |
| 59 | Adair County | 21.8 |
| 60 | Ringgold County | 21.8 |
| 61 | Kossuth County | 21.7 |
| 62 | Fremont County | 21.7 |
| 63 | Black Hawk County | 21.7 |
| 64 | Montgomery County | 21.6 |
| 65 | Dubuque County | 21.6 |
| 66 | Greene County | 21.6 |
| 67 | Lee County | 21.6 |
| 68 | Clay County | 21.5 |
| 69 | Adams County | 21.5 |
| 70 | Butler County | 21.4 |
| 70 | Jasper County | 21.4 |
| 72 | Clayton County | 21.4 |
| 73 | Hancock County | 21.4 |
| 74 | Guthrie County | 21.4 |
| 75 | Webster County | 21.3 |
| 76 | Calhoun County | 21.3 |
| 77 | Jackson County | 21.3 |
| 78 | Union County | 21.2 |
| 79 | Monona County | 21.1 |
| 80 | Louisa County | 20.9 |
| 81 | Cedar County | 20.8 |
| 82 | Des Moines County | 20.8 |
| 83 | Appanoose County | 20.8 |
| 84 | Boone County | 20.7 |
| 85 | Fayette County | 20.6 |
| 86 | Emmet County | 20.5 |
| 87 | Osceola County | 20.5 |
| 88 | Henry County | 20.4 |
| 89 | Winnebago County | 20.4 |
| 90 | Hardin County | 20.3 |
| 91 | Jones County | 20.1 |
| 92 | Cerro Gordo County | 19.5 |
| 93 | Johnson County | 19 |
| 94 | Poweshiek County | 18.9 |
| 95 | Page County | 18.8 |
| 96 | Winneshiek County | 18.4 |
| 97 | Dickinson County | 18.3 |
| 98 | Jefferson County | 17.9 |
| 99 | Story County | 15.9 |