Iowa Population By County in 2018
Updated on January 29, 2024.
Based on the US Census Vintage data estimates, in 2018, the population of Iowa was 3,149,900. Among all Iowa counties, Polk[object Promise] had the highest population (486,222), followed by Linn[object Promise] (226,060), and Scott[object Promise] (173,019). Adams[object Promise] was the least populated county (3,628).
Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.
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 in 2018
Iowa Population By County in 2018
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| County | Population | % of State Population |
|---|---|---|
| Adair | 7028 | 0.22 |
| Adams | 3628 | 0.12 |
| Allamakee | 13832 | 0.44 |
| Appanoose | 12467 | 0.40 |
| Audubon | 5482 | 0.17 |
| Benton | 25546 | 0.81 |
| Black Hawk | 131769 | 4.18 |
| Boone | 26356 | 0.84 |
| Bremer | 25022 | 0.79 |
| Buchanan | 21140 | 0.67 |
| Buena Vista | 19807 | 0.63 |
| Butler | 14516 | 0.46 |
| Calhoun | 9653 | 0.31 |
| Carroll | 20101 | 0.64 |
| Cass | 12959 | 0.41 |
| Cedar | 18508 | 0.59 |
| Cerro Gordo | 42643 | 1.35 |
| Cherokee | 11281 | 0.36 |
| Chickasaw | 11965 | 0.38 |
| Clarke | 9489 | 0.30 |
| Clay | 16167 | 0.51 |
| Clayton | 17515 | 0.56 |
| Clinton | 46506 | 1.48 |
| Crawford | 17081 | 0.54 |
| Dallas | 89999 | 2.86 |
| Davis | 8967 | 0.28 |
| Decatur | 7901 | 0.25 |
| Delaware | 17115 | 0.54 |
| Des Moines | 39259 | 1.25 |
| Dickinson | 17159 | 0.55 |
| Dubuque | 96961 | 3.08 |
| Emmet | 9276 | 0.29 |
| Fayette | 19643 | 0.62 |
| Floyd | 15784 | 0.50 |
| Franklin | 10081 | 0.32 |
| Fremont | 6956 | 0.22 |
| Greene | 8971 | 0.28 |
| Grundy | 12268 | 0.39 |
| Guthrie | 10719 | 0.34 |
| Hamilton | 14887 | 0.47 |
| Hancock | 10726 | 0.34 |
| Hardin | 16965 | 0.54 |
| Harrison | 14086 | 0.45 |
| Henry | 20015 | 0.64 |
| Howard | 9185 | 0.29 |
| Humboldt | 9520 | 0.30 |
| Ida | 6829 | 0.22 |
| Iowa | 16150 | 0.51 |
| Jackson | 19375 | 0.62 |
| Jasper | 37121 | 1.18 |
| Jefferson | 18102 | 0.57 |
| Johnson | 151003 | 4.79 |
| Jones | 20627 | 0.66 |
| Keokuk | 10221 | 0.32 |
| Kossuth | 14834 | 0.47 |
| Lee | 33929 | 1.08 |
| Linn | 226060 | 7.18 |
| Louisa | 11135 | 0.35 |
| Lucas | 8590 | 0.27 |
| Lyon | 11849 | 0.38 |
| Madison | 16140 | 0.51 |
| Mahaska | 22203 | 0.71 |
| Marion | 33251 | 1.06 |
| Marshall | 39879 | 1.27 |
| Mills | 15122 | 0.48 |
| Mitchell | 10536 | 0.33 |
| Monona | 8649 | 0.28 |
| Monroe | 7738 | 0.25 |
| Montgomery | 9976 | 0.32 |
| Muscatine | 42784 | 1.36 |
| O'Brien | 13806 | 0.44 |
| Osceola | 6020 | 0.19 |
| Page | 15227 | 0.48 |
| Palo Alto | 8910 | 0.28 |
| Plymouth | 25024 | 0.79 |
| Pocahontas | 6709 | 0.21 |
| Polk | 486222 | 15.44 |
| Pottawattamie | 93445 | 2.97 |
| Poweshiek | 18461 | 0.59 |
| Ringgold | 4921 | 0.16 |
| Sac | 9675 | 0.31 |
| Scott | 173019 | 5.49 |
| Shelby | 11564 | 0.37 |
| Sioux | 34767 | 1.10 |
| Story | 96749 | 3.07 |
| Tama | 16853 | 0.54 |
| Taylor | 6190 | 0.20 |
| Union | 12297 | 0.39 |
| Van Buren | 7008 | 0.22 |
| Wapello | 35060 | 1.11 |
| Warren | 51053 | 1.62 |
| Washington | 22095 | 0.70 |
| Wayne | 6376 | 0.20 |
| Webster | 36361 | 1.15 |
| Winnebago | 10555 | 0.34 |
| Winneshiek | 20026 | 0.64 |
| Woodbury | 102415 | 3.25 |
| Worth | 7416 | 0.24 |
| Wright | 12669 | 0.40 |