Ranking of Iowa Counties By Population in 2015
Updated on January 28, 2024.
Based on the US Census Vintage data estimates, in 2015, the Population for Iowa was 3.12M. Among all Iowa counties, Polk County had the highest population (467.52K), followed by Linn County (220.39K), and Scott County (172.07K).
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), 2015 Census.
See this for other years:
Ranking of Iowa Counties By Population in 2015
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| Rank | County | Population |
|---|---|---|
| 1 | Polk County | 467517 |
| 2 | Linn County | 220392 |
| 3 | Scott County | 172072 |
| 4 | Johnson County | 145114 |
| 5 | Black Hawk County | 133764 |
| 6 | Woodbury County | 102532 |
| 7 | Dubuque County | 96934 |
| 8 | Story County | 96744 |
| 9 | Pottawattamie County | 93657 |
| 10 | Dallas County | 80658 |
| 11 | Warren County | 48486 |
| 12 | Clinton County | 47593 |
| 13 | Muscatine County | 43069 |
| 14 | Cerro Gordo County | 43006 |
| 15 | Marshall County | 40340 |
| 16 | Des Moines County | 39909 |
| 17 | Webster County | 37089 |
| 18 | Jasper County | 36762 |
| 19 | Wapello County | 35450 |
| 20 | Lee County | 34916 |
| 21 | Sioux County | 34764 |
| 22 | Marion County | 33123 |
| 23 | Boone County | 26468 |
| 24 | Benton County | 25608 |
| 25 | Plymouth County | 24912 |
| 26 | Bremer County | 24755 |
| 27 | Mahaska County | 22417 |
| 28 | Washington County | 22160 |
| 29 | Buchanan County | 21110 |
| 30 | Winneshiek County | 20756 |
| 31 | Jones County | 20435 |
| 32 | Carroll County | 20421 |
| 33 | Buena Vista County | 20373 |
| 34 | Fayette County | 20143 |
| 35 | Henry County | 19862 |
| 36 | Jackson County | 19363 |
| 37 | Poweshiek County | 18379 |
| 38 | Cedar County | 18257 |
| 39 | Jefferson County | 17913 |
| 40 | Clayton County | 17726 |
| 41 | Delaware County | 17395 |
| 42 | Hardin County | 17257 |
| 43 | Tama County | 17214 |
| 44 | Crawford County | 17069 |
| 45 | Dickinson County | 17009 |
| 46 | Clay County | 16498 |
| 47 | Iowa County | 16293 |
| 48 | Floyd County | 15920 |
| 49 | Madison County | 15727 |
| 50 | Page County | 15466 |
| 51 | Hamilton County | 15220 |
| 52 | Kossuth County | 15150 |
| 53 | Mills County | 14885 |
| 54 | Butler County | 14880 |
| 55 | Harrison County | 14145 |
| 56 | O'Brien County | 13927 |
| 57 | Allamakee County | 13881 |
| 58 | Cass County | 13354 |
| 59 | Wright County | 12843 |
| 60 | Appanoose County | 12587 |
| 61 | Union County | 12431 |
| 62 | Grundy County | 12402 |
| 63 | Chickasaw County | 12152 |
| 64 | Shelby County | 11799 |
| 65 | Lyon County | 11755 |
| 66 | Cherokee County | 11488 |
| 67 | Louisa County | 11289 |
| 68 | Hancock County | 11029 |
| 69 | Mitchell County | 10670 |
| 70 | Guthrie County | 10653 |
| 71 | Winnebago County | 10612 |
| 72 | Franklin County | 10318 |
| 73 | Keokuk County | 10169 |
| 74 | Montgomery County | 10153 |
| 75 | Sac County | 9961 |
| 76 | Calhoun County | 9801 |
| 77 | Emmet County | 9708 |
| 78 | Humboldt County | 9562 |
| 79 | Howard County | 9322 |
| 80 | Clarke County | 9213 |
| 81 | Palo Alto County | 9137 |
| 82 | Greene County | 8947 |
| 83 | Monona County | 8865 |
| 84 | Davis County | 8774 |
| 85 | Lucas County | 8609 |
| 86 | Decatur County | 8145 |
| 87 | Monroe County | 7919 |
| 88 | Worth County | 7503 |
| 89 | Van Buren County | 7297 |
| 90 | Adair County | 7142 |
| 91 | Pocahontas County | 6970 |
| 92 | Ida County | 6967 |
| 93 | Fremont County | 6910 |
| 94 | Wayne County | 6359 |
| 95 | Taylor County | 6243 |
| 96 | Osceola County | 6161 |
| 97 | Audubon County | 5707 |
| 98 | Ringgold County | 4978 |
| 99 | Adams County | 3752 |