Iowa Population By County in 2018
Updated on January 29, 2024.
According to the US Census Bureau population estimates, there were 3,149,900 people living in Iowa in 2018. Polk[object Promise] County was the most populated county with 486,222 residents, followed by Linn[object Promise] County with 226,060 residents, and Scott[object Promise] County with 173,019 residents. Adams[object Promise] 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 for each county in Iowa in 2018. The data can also be explored further by sorting and filtering with the table below.
You can see similar information for other states and by state for the United States.
Related Topics: Iowa Census Vintage Data Topic List.
Data Source: US Census Bureau (Vintage).
See this for other years:
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% |