| A to D | E to L | M to W |
| Adair County | Emmet County | Madison County |
| Adams County | Fayette County | Mahaska County |
| Allamakee County | Floyd County | Marion County |
| Appanoose County | Franklin County | Marshall County |
| Audubon County | Fremont County | Mills County |
| Benton County | Greene County | Mitchell County |
Boone County | ||
| Bremer County | Grundy County | Monona County |
| Buchanan County | Guthrie County | Monroe County |
| Buena Vista County | Hamilton County | Montgomery County |
| Butler County | Hancock County | Muscatine County |
| Calhoun County | Hardin County | O’Brien County |
| Carroll County | Harrison County | Osceola County |
| Cass County | Henry County | Page County |
| Cerro Gordo County | ||
| Clarke County | Howard County | Palo Alto County |
| Clay County | Humboldt County | Plymouth County |
| Clayton County | Ida County | Pocahontas County |
| Clinton County | Iowa County | Polk County |
| Crawford County | Jackson County | Pottawattamie County |
| Dallas County | Jasper County | Poweshiek County |
| Davis County | Jefferson County | Ringgold County |
| Decatur County | Johnson County | Sac County |
| Delaware County | Jones County | Scott County |
| Des Moines County | Keokuk County | Shelby County |
| Dickinson County | Kossuth County | Sioux County |
| Dubuque County | Lee County | Story County |
| Linn County | Tama County | |
| Louisa County | Taylor County | |
| Lucas County | Union County | |
| Lyon County | Van Buren County | |
| Wapello County | ||
| Warren County | ||
| Washington County | ||
| Wayne County | ||
| Webster County | ||
| Winnebago County | ||
| Winneshiek County | ||
| Woodbury County | ||
| Worth County | ||
| Wright County |
