# Counties in Iowa by population aged 18 to 64, 2025

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

- Indicator id: `population_18_64_share`
- Unit: %
- Definition: Residents aged 18 to 64 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 18 to 64 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 18 to 64 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-18-64/iowa-counties

| Rank | Place | % |
|---:|---|---:|
| 1 | Story County | 69.1 |
| 2 | Johnson County | 65.7 |
| 3 | Polk County | 60.8 |
| 4 | Dallas County | 60 |
| 5 | Linn County | 59.1 |
| 6 | Black Hawk County | 59 |
| 7 | Scott County | 58.3 |
| 8 | Woodbury County | 58.2 |
| 9 | Warren County | 57.6 |
| 10 | Webster County | 57.5 |
| 11 | Pottawattamie County | 57.4 |
| 12 | Muscatine County | 57.4 |
| 13 | Wapello County | 57.3 |
| 14 | Jones County | 57.1 |
| 15 | Henry County | 57.1 |
| 16 | Jasper County | 56.9 |
| 17 | Poweshiek County | 56.9 |
| 18 | Dubuque County | 56.9 |
| 19 | Boone County | 56.7 |
| 20 | Union County | 56.4 |
| 21 | Louisa County | 56.2 |
| 22 | Buena Vista County | 56.1 |
| 23 | Cedar County | 55.9 |
| 24 | Marion County | 55.9 |
| 25 | Bremer County | 55.8 |
| 26 | Page County | 55.8 |
| 27 | Osceola County | 55.8 |
| 28 | Benton County | 55.8 |
| 29 | Sioux County | 55.7 |
| 30 | Madison County | 55.7 |
| 31 | Mahaska County | 55.6 |
| 32 | Des Moines County | 55.5 |
| 33 | Mills County | 55.3 |
| 34 | Decatur County | 55.3 |
| 35 | Marshall County | 55.3 |
| 36 | Winneshiek County | 55.1 |
| 37 | Clinton County | 55 |
| 38 | Winnebago County | 54.8 |
| 39 | Monroe County | 54.7 |
| 40 | Hardin County | 54.6 |
| 41 | Clarke County | 54.5 |
| 42 | Iowa County | 54.5 |
| 43 | Plymouth County | 54.3 |
| 44 | Crawford County | 54.1 |
| 45 | Harrison County | 54 |
| 46 | Fayette County | 54 |
| 47 | Emmet County | 53.9 |
| 48 | O'Brien County | 53.9 |
| 49 | Cerro Gordo County | 53.8 |
| 50 | Tama County | 53.8 |
| 51 | Appanoose County | 53.7 |
| 52 | Lyon County | 53.7 |
| 53 | Lee County | 53.6 |
| 54 | Buchanan County | 53.6 |
| 55 | Clay County | 53.6 |
| 56 | Jackson County | 53.5 |
| 57 | Keokuk County | 53.5 |
| 58 | Delaware County | 53.4 |
| 59 | Montgomery County | 53.4 |
| 60 | Franklin County | 53.3 |
| 61 | Floyd County | 53.3 |
| 62 | Washington County | 53.2 |
| 63 | Worth County | 53.2 |
| 64 | Hamilton County | 53.2 |
| 65 | Fremont County | 53.1 |
| 66 | Calhoun County | 53 |
| 67 | Adair County | 53 |
| 68 | Grundy County | 53 |
| 69 | Carroll County | 52.8 |
| 70 | Wright County | 52.8 |
| 71 | Ida County | 52.8 |
| 72 | Chickasaw County | 52.5 |
| 73 | Lucas County | 52.3 |
| 74 | Humboldt County | 52.3 |
| 75 | Howard County | 52.3 |
| 76 | Adams County | 52.3 |
| 77 | Cass County | 52.3 |
| 78 | Taylor County | 52.2 |
| 79 | Shelby County | 52.1 |
| 80 | Palo Alto County | 52.1 |
| 81 | Monona County | 51.8 |
| 82 | Mitchell County | 51.8 |
| 83 | Guthrie County | 51.7 |
| 84 | Greene County | 51.7 |
| 85 | Butler County | 51.6 |
| 86 | Hancock County | 51.6 |
| 87 | Sac County | 51.4 |
| 88 | Kossuth County | 51.4 |
| 89 | Jefferson County | 51.4 |
| 90 | Wayne County | 51.3 |
| 91 | Pocahontas County | 51.2 |
| 92 | Dickinson County | 51.1 |
| 93 | Clayton County | 50.9 |
| 94 | Audubon County | 50.9 |
| 95 | Allamakee County | 50.9 |
| 96 | Cherokee County | 50.6 |
| 97 | Van Buren County | 50.5 |
| 98 | Davis County | 50.4 |
| 99 | Ringgold County | 49.8 |