# Counties in Iowa by median age on 1 July (US county estimates), 2025

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

- Indicator id: `median_age_pep`
- Unit: years
- Definition: Age that divides the resident population of a US county into two halves of equal size on 1 July, from Census Bureau population estimates calculated by single year of age.
- Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage (https://www.census.gov/programs-surveys/popest/data/data-sets.html)
- Publisher page: https://invokely.ai/en/publishers/us-census-bureau
- Retrieved: 2026-10-12
- Citation: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/median-age-july-1-us-counties/iowa-counties

| Rank | Place | years |
|---:|---|---:|
| 1 | Dickinson County | 49.5 |
| 2 | Guthrie County | 46.4 |
| 3 | Clayton County | 46.3 |
| 4 | Jefferson County | 46.2 |
| 5 | Adams County | 45.9 |
| 5 | Audubon County | 45.9 |
| 7 | Butler County | 45.7 |
| 8 | Fremont County | 45.5 |
| 9 | Monona County | 45.4 |
| 9 | Sac County | 45.4 |
| 11 | Appanoose County | 45.3 |
| 11 | Cerro Gordo County | 45.3 |
| 11 | Jackson County | 45.3 |
| 14 | Greene County | 45.2 |
| 14 | Kossuth County | 45.2 |
| 16 | Hancock County | 45.1 |
| 17 | Ringgold County | 45 |
| 18 | Shelby County | 44.5 |
| 19 | Cedar County | 44.4 |
| 20 | Cass County | 44.3 |
| 20 | Fayette County | 44.3 |
| 22 | Cherokee County | 44.2 |
| 22 | Page County | 44.2 |
| 22 | Pocahontas County | 44.2 |
| 22 | Winneshiek County | 44.2 |
| 26 | Hardin County | 44.1 |
| 27 | Jones County | 44 |
| 27 | Osceola County | 44 |
| 27 | Van Buren County | 44 |
| 30 | Delaware County | 43.9 |
| 30 | Lee County | 43.9 |
| 30 | Louisa County | 43.9 |
| 30 | Montgomery County | 43.9 |
| 30 | Worth County | 43.9 |
| 35 | Adair County | 43.7 |
| 35 | Iowa County | 43.7 |
| 37 | Chickasaw County | 43.6 |
| 37 | Clay County | 43.6 |
| 39 | Allamakee County | 43.5 |
| 39 | Calhoun County | 43.5 |
| 41 | Floyd County | 43.4 |
| 41 | Keokuk County | 43.4 |
| 43 | Harrison County | 43.3 |
| 43 | Mills County | 43.3 |
| 45 | Mitchell County | 43.2 |
| 46 | Des Moines County | 43.1 |
| 46 | Emmet County | 43.1 |
| 46 | Ida County | 43.1 |
| 46 | Taylor County | 43.1 |
| 50 | Monroe County | 43 |
| 51 | Winnebago County | 42.9 |
| 52 | Benton County | 42.8 |
| 52 | Boone County | 42.8 |
| 54 | Clinton County | 42.7 |
| 54 | Humboldt County | 42.7 |
| 56 | Carroll County | 42.6 |
| 57 | Palo Alto County | 42.5 |
| 58 | Grundy County | 42.4 |
| 59 | Henry County | 42.3 |
| 59 | Howard County | 42.3 |
| 59 | Jasper County | 42.3 |
| 62 | Hamilton County | 42.2 |
| 62 | Madison County | 42.2 |
| 64 | Franklin County | 42 |
| 64 | Lucas County | 42 |
| 64 | Tama County | 42 |
| 67 | Poweshiek County | 41.6 |
| 68 | Union County | 41.4 |
| 69 | Muscatine County | 41.3 |
| 70 | Plymouth County | 41.2 |
| 70 | Pottawattamie County | 41.2 |
| 72 | Marion County | 41.1 |
| 72 | Washington County | 41.1 |
| 74 | Clarke County | 40.5 |
| 75 | Bremer County | 40.4 |
| 75 | Buchanan County | 40.4 |
| 77 | Mahaska County | 40.2 |
| 77 | Scott County | 40.2 |
| 79 | Dubuque County | 40 |
| 80 | O'Brien County | 39.8 |
| 81 | Wright County | 39.6 |
| 82 | Wapello County | 39.5 |
| 83 | Linn County | 39.4 |
| 83 | Wayne County | 39.4 |
| 83 | Webster County | 39.4 |
| 86 | Warren County | 39.2 |
| 87 | Marshall County | 38.8 |
| 88 | Crawford County | 38 |
| 89 | Decatur County | 37.6 |
| 90 | Lyon County | 37.4 |
| 91 | Polk County | 36.9 |
| 92 | Black Hawk County | 36.7 |
| 92 | Buena Vista County | 36.7 |
| 92 | Dallas County | 36.7 |
| 95 | Woodbury County | 36.3 |
| 96 | Davis County | 36.1 |
| 97 | Sioux County | 33.7 |
| 98 | Johnson County | 32.6 |
| 99 | Story County | 26.9 |