Iowa Population By County in 2018
Updated on December 2, 2021.
According to the US Census Bureau population estimates, there were 3,149,900 people living in Iowa in 2018. Polk County was the most populated county with 486,222 residents, followed by Linn County with 226,060 residents, and Scott County with 173,019 residents. Adams County with a population of 3,628 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 | 7,028 | 0.22% |
| Adams | 3,628 | 0.12% |
| Allamakee | 13,832 | 0.44% |
| Appanoose | 12,467 | 0.40% |
| Audubon | 5,482 | 0.17% |
| Benton | 25,546 | 0.81% |
| Black Hawk | 131,769 | 4.18% |
| Boone | 26,356 | 0.84% |
| Bremer | 25,022 | 0.79% |
| Buchanan | 21,140 | 0.67% |
| Buena Vista | 19,807 | 0.63% |
| Butler | 14,516 | 0.46% |
| Calhoun | 9,653 | 0.31% |
| Carroll | 20,101 | 0.64% |
| Cass | 12,959 | 0.41% |
| Cedar | 18,508 | 0.59% |
| Cerro Gordo | 42,643 | 1.35% |
| Cherokee | 11,281 | 0.36% |
| Chickasaw | 11,965 | 0.38% |
| Clarke | 9,489 | 0.30% |
| Clay | 16,167 | 0.51% |
| Clayton | 17,515 | 0.56% |
| Clinton | 46,506 | 1.48% |
| Crawford | 17,081 | 0.54% |
| Dallas | 89,999 | 2.86% |
| Davis | 8,967 | 0.28% |
| Decatur | 7,901 | 0.25% |
| Delaware | 17,115 | 0.54% |
| Des Moines | 39,259 | 1.25% |
| Dickinson | 17,159 | 0.55% |
| Dubuque | 96,961 | 3.08% |
| Emmet | 9,276 | 0.29% |
| Fayette | 19,643 | 0.62% |
| Floyd | 15,784 | 0.50% |
| Franklin | 10,081 | 0.32% |
| Fremont | 6,956 | 0.22% |
| Greene | 8,971 | 0.28% |
| Grundy | 12,268 | 0.39% |
| Guthrie | 10,719 | 0.34% |
| Hamilton | 14,887 | 0.47% |
| Hancock | 10,726 | 0.34% |
| Hardin | 16,965 | 0.54% |
| Harrison | 14,086 | 0.45% |
| Henry | 20,015 | 0.64% |
| Howard | 9,185 | 0.29% |
| Humboldt | 9,520 | 0.30% |
| Ida | 6,829 | 0.22% |
| Iowa | 16,150 | 0.51% |
| Jackson | 19,375 | 0.62% |
| Jasper | 37,121 | 1.18% |
| Jefferson | 18,102 | 0.57% |
| Johnson | 151,003 | 4.79% |
| Jones | 20,627 | 0.66% |
| Keokuk | 10,221 | 0.32% |
| Kossuth | 14,834 | 0.47% |
| Lee | 33,929 | 1.08% |
| Linn | 226,060 | 7.18% |
| Louisa | 11,135 | 0.35% |
| Lucas | 8,590 | 0.27% |
| Lyon | 11,849 | 0.38% |
| Madison | 16,140 | 0.51% |
| Mahaska | 22,203 | 0.71% |
| Marion | 33,251 | 1.06% |
| Marshall | 39,879 | 1.27% |
| Mills | 15,122 | 0.48% |
| Mitchell | 10,536 | 0.33% |
| Monona | 8,649 | 0.28% |
| Monroe | 7,738 | 0.25% |
| Montgomery | 9,976 | 0.32% |
| Muscatine | 42,784 | 1.36% |
| O'Brien | 13,806 | 0.44% |
| Osceola | 6,020 | 0.19% |
| Page | 15,227 | 0.48% |
| Palo Alto | 8,910 | 0.28% |
| Plymouth | 25,024 | 0.79% |
| Pocahontas | 6,709 | 0.21% |
| Polk | 486,222 | 15.44% |
| Pottawattamie | 93,445 | 2.97% |
| Poweshiek | 18,461 | 0.59% |
| Ringgold | 4,921 | 0.16% |
| Sac | 9,675 | 0.31% |
| Scott | 173,019 | 5.49% |
| Shelby | 11,564 | 0.37% |
| Sioux | 34,767 | 1.10% |
| Story | 96,749 | 3.07% |
| Tama | 16,853 | 0.54% |
| Taylor | 6,190 | 0.20% |
| Union | 12,297 | 0.39% |
| Van Buren | 7,008 | 0.22% |
| Wapello | 35,060 | 1.11% |
| Warren | 51,053 | 1.62% |
| Washington | 22,095 | 0.70% |
| Wayne | 6,376 | 0.20% |
| Webster | 36,361 | 1.15% |
| Winnebago | 10,555 | 0.34% |
| Winneshiek | 20,026 | 0.64% |
| Woodbury | 102,415 | 3.25% |
| Worth | 7,416 | 0.24% |
| Wright | 12,669 | 0.40% |
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