Ranking of Iowa Counties By Population in 2018
Updated on January 28, 2024.
Based on the US Census Vintage data estimates, in 2018, the Population for Iowa was 3.15M. Among all Iowa counties, Polk County had the highest population (486.22K), followed by Linn County (226.06K), and Scott County (173.02K).
The chart below shows the top 10 counties, and the table below shows the ranking of all Iowa counties.
You can see similar ranking information for related topics, and for other states. You can also see the ranking of all counties in the United States.
Related Topics: Iowa Census Vintage Data Topic List.
Data Source: US Census Bureau (Vintage), 2018 Census.
See this for other years:
Ranking of Iowa Counties By Population in 2018
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| Rank | County | Population |
|---|---|---|
| 1 | Polk County | 486222 |
| 2 | Linn County | 226060 |
| 3 | Scott County | 173019 |
| 4 | Johnson County | 151003 |
| 5 | Black Hawk County | 131769 |
| 6 | Woodbury County | 102415 |
| 7 | Dubuque County | 96961 |
| 8 | Story County | 96749 |
| 9 | Pottawattamie County | 93445 |
| 10 | Dallas County | 89999 |
| 11 | Warren County | 51053 |
| 12 | Clinton County | 46506 |
| 13 | Muscatine County | 42784 |
| 14 | Cerro Gordo County | 42643 |
| 15 | Marshall County | 39879 |
| 16 | Des Moines County | 39259 |
| 17 | Jasper County | 37121 |
| 18 | Webster County | 36361 |
| 19 | Wapello County | 35060 |
| 20 | Sioux County | 34767 |
| 21 | Lee County | 33929 |
| 22 | Marion County | 33251 |
| 23 | Boone County | 26356 |
| 24 | Benton County | 25546 |
| 25 | Plymouth County | 25024 |
| 26 | Bremer County | 25022 |
| 27 | Mahaska County | 22203 |
| 28 | Washington County | 22095 |
| 29 | Buchanan County | 21140 |
| 30 | Jones County | 20627 |
| 31 | Carroll County | 20101 |
| 32 | Winneshiek County | 20026 |
| 33 | Henry County | 20015 |
| 34 | Buena Vista County | 19807 |
| 35 | Fayette County | 19643 |
| 36 | Jackson County | 19375 |
| 37 | Cedar County | 18508 |
| 38 | Poweshiek County | 18461 |
| 39 | Jefferson County | 18102 |
| 40 | Clayton County | 17515 |
| 41 | Dickinson County | 17159 |
| 42 | Delaware County | 17115 |
| 43 | Crawford County | 17081 |
| 44 | Hardin County | 16965 |
| 45 | Tama County | 16853 |
| 46 | Clay County | 16167 |
| 47 | Iowa County | 16150 |
| 48 | Madison County | 16140 |
| 49 | Floyd County | 15784 |
| 50 | Page County | 15227 |
| 51 | Mills County | 15122 |
| 52 | Hamilton County | 14887 |
| 53 | Kossuth County | 14834 |
| 54 | Butler County | 14516 |
| 55 | Harrison County | 14086 |
| 56 | Allamakee County | 13832 |
| 57 | O'Brien County | 13806 |
| 58 | Cass County | 12959 |
| 59 | Wright County | 12669 |
| 60 | Appanoose County | 12467 |
| 61 | Union County | 12297 |
| 62 | Grundy County | 12268 |
| 63 | Chickasaw County | 11965 |
| 64 | Lyon County | 11849 |
| 65 | Shelby County | 11564 |
| 66 | Cherokee County | 11281 |
| 67 | Louisa County | 11135 |
| 68 | Hancock County | 10726 |
| 69 | Guthrie County | 10719 |
| 70 | Winnebago County | 10555 |
| 71 | Mitchell County | 10536 |
| 72 | Keokuk County | 10221 |
| 73 | Franklin County | 10081 |
| 74 | Montgomery County | 9976 |
| 75 | Sac County | 9675 |
| 76 | Calhoun County | 9653 |
| 77 | Humboldt County | 9520 |
| 78 | Clarke County | 9489 |
| 79 | Emmet County | 9276 |
| 80 | Howard County | 9185 |
| 81 | Greene County | 8971 |
| 82 | Davis County | 8967 |
| 83 | Palo Alto County | 8910 |
| 84 | Monona County | 8649 |
| 85 | Lucas County | 8590 |
| 86 | Decatur County | 7901 |
| 87 | Monroe County | 7738 |
| 88 | Worth County | 7416 |
| 89 | Adair County | 7028 |
| 90 | Van Buren County | 7008 |
| 91 | Fremont County | 6956 |
| 92 | Ida County | 6829 |
| 93 | Pocahontas County | 6709 |
| 94 | Wayne County | 6376 |
| 95 | Taylor County | 6190 |
| 96 | Osceola County | 6020 |
| 97 | Audubon County | 5482 |
| 98 | Ringgold County | 4921 |
| 99 | Adams County | 3628 |