# Counties in Iowa by population, 2025

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

- Indicator id: `population`
- Unit: persons
- Definition: Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.
- Source: U.S. Census Bureau, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program) (https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/)
- Retrieved: 2026-10-08
- Citation: U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.
- Web page: https://invokely.ai/rankings/population/iowa-counties
- CSV: https://invokely.ai/download/rankings/population/iowa-counties.csv

| Rank | Place | persons |
|---:|---|---:|
| 1 | Polk County | 516,546 |
| 2 | Linn County | 232,028 |
| 3 | Scott County | 175,259 |
| 4 | Johnson County | 160,044 |
| 5 | Black Hawk County | 131,532 |
| 6 | Dallas County | 118,457 |
| 7 | Woodbury County | 106,649 |
| 8 | Story County | 101,291 |
| 9 | Dubuque County | 99,381 |
| 10 | Pottawattamie County | 92,996 |
| 11 | Warren County | 57,331 |
| 12 | Clinton County | 46,002 |
| 13 | Cerro Gordo County | 42,372 |
| 14 | Muscatine County | 41,853 |
| 15 | Marshall County | 39,890 |
| 16 | Jasper County | 38,153 |
| 17 | Des Moines County | 38,077 |
| 18 | Webster County | 36,838 |
| 19 | Sioux County | 36,774 |
| 20 | Wapello County | 35,210 |
| 21 | Marion County | 34,192 |
| 22 | Lee County | 32,306 |
| 23 | Boone County | 26,799 |
| 24 | Benton County | 26,004 |
| 25 | Plymouth County | 25,697 |
| 26 | Bremer County | 25,296 |
| 27 | Washington County | 22,667 |
| 28 | Mahaska County | 21,880 |
| 29 | Jones County | 21,253 |
| 30 | Buchanan County | 20,883 |
| 31 | Buena Vista County | 20,449 |
| 32 | Carroll County | 20,303 |
| 33 | Winneshiek County | 19,733 |
| 34 | Henry County | 19,349 |
| 35 | Jackson County | 19,288 |
| 36 | Fayette County | 19,047 |
| 37 | Poweshiek County | 18,368 |
| 38 | Cedar County | 18,359 |
| 39 | Dickinson County | 18,077 |
| 40 | Delaware County | 17,674 |
| 41 | Madison County | 17,270 |
| 42 | Clayton County | 16,845 |
| 43 | Tama County | 16,796 |
| 44 | Iowa County | 16,504 |
| 45 | Hardin County | 16,455 |
| 46 | Crawford County | 16,237 |
| 47 | Clay County | 16,202 |
| 48 | Jefferson County | 15,291 |
| 49 | Hamilton County | 14,944 |
| 50 | Floyd County | 14,901 |
| 51 | Page County | 14,856 |
| 52 | Mills County | 14,793 |
| 53 | Harrison County | 14,623 |
| 54 | Kossuth County | 14,322 |
| 55 | Allamakee County | 14,238 |
| 56 | O'Brien County | 14,220 |
| 57 | Butler County | 14,049 |
| 58 | Cass County | 12,960 |
| 59 | Wright County | 12,801 |
| 60 | Grundy County | 12,361 |
| 61 | Lyon County | 12,354 |
| 62 | Appanoose County | 12,077 |
| 63 | Union County | 11,829 |
| 64 | Shelby County | 11,689 |
| 65 | Chickasaw County | 11,663 |
| 66 | Cherokee County | 11,369 |
| 67 | Guthrie County | 10,782 |
| 68 | Mitchell County | 10,650 |
| 69 | Hancock County | 10,528 |
| 70 | Louisa County | 10,416 |
| 71 | Winnebago County | 10,251 |
| 72 | Montgomery County | 10,002 |
| 73 | Franklin County | 9,868 |
| 74 | Keokuk County | 9,797 |
| 75 | Clarke County | 9,574 |
| 76 | Calhoun County | 9,562 |
| 77 | Sac County | 9,525 |
| 78 | Howard County | 9,415 |
| 79 | Humboldt County | 9,409 |
| 80 | Davis County | 9,230 |
| 81 | Emmet County | 9,107 |
| 82 | Palo Alto County | 8,899 |
| 83 | Lucas County | 8,847 |
| 84 | Greene County | 8,658 |
| 85 | Monona County | 8,539 |
| 86 | Decatur County | 7,655 |
| 87 | Monroe County | 7,406 |
| 88 | Adair County | 7,403 |
| 89 | Worth County | 7,338 |
| 90 | Van Buren County | 7,131 |
| 91 | Pocahontas County | 6,819 |
| 92 | Ida County | 6,777 |
| 93 | Wayne County | 6,738 |
| 94 | Fremont County | 6,522 |
| 95 | Osceola County | 5,980 |
| 96 | Taylor County | 5,835 |
| 97 | Audubon County | 5,509 |
| 98 | Ringgold County | 4,642 |
| 99 | Adams County | 3,617 |