Iowa Population By County in 2018
Updated on June 22, 2021.
According to the US Census Bureau population estimates, there were 3,148,618 people living in Iowa in 2018. Polk County was the most populated county with 485,833 residents, followed by Linn County with 225,763 residents, and Scott County with 172,803 residents. Adams County with a population of 3,644 was the least populated county in Iowa in 2018.
Use the map below to interactively explore the population of each county in Iowa in 2018. The data can also be explored further by sorting and filtering with the table below.
Hover/Click on the counties to see the values.
Iowa Population By County (2018)
Table of Iowa Population By County in 2018
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| County | Population | % of State Population |
|---|---|---|
| Adair | 7,074 | 0.23% |
| Adams | 3,644 | 0.12% |
| Allamakee | 13,852 | 0.44% |
| Appanoose | 12,401 | 0.39% |
| Audubon | 5,471 | 0.17% |
| Benton | 25,625 | 0.81% |
| Black Hawk | 131,723 | 4.18% |
| Boone | 26,312 | 0.84% |
| Bremer | 24,941 | 0.79% |
| Buchanan | 21,178 | 0.67% |
| Buena Vista | 19,826 | 0.63% |
| Butler | 14,525 | 0.46% |
| Calhoun | 9,711 | 0.31% |
| Carroll | 20,153 | 0.64% |
| Cass | 12,948 | 0.41% |
| Cedar | 18,564 | 0.59% |
| Cerro Gordo | 42,642 | 1.35% |
| Cherokee | 11,295 | 0.36% |
| Chickasaw | 11,952 | 0.38% |
| Clarke | 9,502 | 0.30% |
| Clay | 16,106 | 0.51% |
| Clayton | 17,540 | 0.56% |
| Clinton | 46,437 | 1.48% |
| Crawford | 17,089 | 0.54% |
| Dallas | 89,953 | 2.86% |
| Davis | 8,972 | 0.28% |
| Decatur | 7,890 | 0.25% |
| Delaware | 17,081 | 0.54% |
| Des Moines | 39,149 | 1.24% |
| Dickinson | 17,121 | 0.54% |
| Dubuque | 96,922 | 3.08% |
| Emmet | 9,277 | 0.30% |
| Fayette | 19,679 | 0.63% |
| Floyd | 15,752 | 0.50% |
| Franklin | 10,085 | 0.32% |
| Fremont | 6,981 | 0.22% |
| Greene | 8,965 | 0.28% |
| Grundy | 12,272 | 0.39% |
| Guthrie | 10,720 | 0.34% |
| Hamilton | 14,886 | 0.47% |
| Hancock | 10,710 | 0.34% |
| Hardin | 16,937 | 0.54% |
| Harrison | 14,105 | 0.45% |
| Henry | 20,033 | 0.64% |
| Howard | 9,172 | 0.29% |
| Humboldt | 9,559 | 0.30% |
| Ida | 6,846 | 0.22% |
| Iowa | 16,155 | 0.51% |
| Jackson | 19,427 | 0.62% |
| Jasper | 37,189 | 1.18% |
| Jefferson | 18,256 | 0.58% |
| Johnson | 150,549 | 4.78% |
| Jones | 20,673 | 0.66% |
| Keokuk | 10,213 | 0.32% |
| Kossuth | 14,878 | 0.47% |
| Lee | 33,909 | 1.08% |
| Linn | 225,763 | 7.17% |
| Louisa | 11,153 | 0.35% |
| Lucas | 8,617 | 0.27% |
| Lyon | 11,815 | 0.38% |
| Madison | 16,206 | 0.52% |
| Mahaska | 22,018 | 0.70% |
| Marion | 33,259 | 1.06% |
| Marshall | 39,888 | 1.27% |
| Mills | 15,068 | 0.48% |
| Mitchell | 10,571 | 0.34% |
| Monona | 8,659 | 0.28% |
| Monroe | 7,768 | 0.25% |
| Montgomery | 9,961 | 0.32% |
| Muscatine | 42,874 | 1.36% |
| O'Brien | 13,798 | 0.44% |
| Osceola | 6,028 | 0.19% |
| Page | 15,229 | 0.48% |
| Palo Alto | 8,903 | 0.28% |
| Plymouth | 25,024 | 0.80% |
| Pocahontas | 6,714 | 0.21% |
| Polk | 485,833 | 15.43% |
| Pottawattamie | 93,264 | 2.96% |
| Poweshiek | 18,467 | 0.59% |
| Ringgold | 4,940 | 0.16% |
| Sac | 9,705 | 0.31% |
| Scott | 172,803 | 5.49% |
| Shelby | 11,559 | 0.37% |
| Sioux | 34,802 | 1.11% |
| Story | 96,781 | 3.07% |
| Tama | 16,869 | 0.54% |
| Taylor | 6,160 | 0.20% |
| Union | 12,298 | 0.39% |
| Van Buren | 7,013 | 0.22% |
| Wapello | 34,991 | 1.11% |
| Warren | 51,014 | 1.62% |
| Washington | 22,058 | 0.70% |
| Wayne | 6,405 | 0.20% |
| Webster | 36,339 | 1.15% |
| Winnebago | 10,539 | 0.34% |
| Winneshiek | 20,017 | 0.64% |
| Woodbury | 102,515 | 3.26% |
| Worth | 7,413 | 0.24% |
| Wright | 12,690 | 0.40% |
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