| Court | Histories | Land | Law | Vital |
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U. S. Federal Census transcription for all Iowa Territory 1840 combined (all 18 counties) census |
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A | B-1 | B-2| C-1 | C-2 | D | E | F | G | H-1 | H-2 | I-J | K | L | M-1 | M-2 | N-O | P | Q | R | S-1 | S-2 | T | U-V | W | X-Y-Z |
| Adair | Adams | Allamakee | Appanoose | Audubon |
| Benton | Black Hawk | Boone | Bremer | Buchanan |
| Buena Vista | Butler | Calhoun | Carroll | Cass |
| Cedar | Cerro Gordo | Cherokee | Chickasaw | Clarke |
| Clay | Clayton | Clinton | Crawford | Dallas |
| Davis | Decatur | Delaware | Des Moines | Dickinson |
| Dubuque | Emmet | Fayette | Floyd | Franklin |
| Fremont | Greene | Grundy | Guthrie | Hamilton |
| Hancock | Hardin | Harrison | Henry | Howard |
| Humboldt | Ida | Iowa | Jackson | Jasper |
| Jefferson | Johnson | Jones | Keokuk | Kossuth |
| Lee | Linn | Louisa | Lucas | Lyon |
| Madison | Mahaska | Marion | Marshall | Mills |
| Mitchell | Monona | Monroe | Montgomery | Muscatine |
| O'Brien | Osceola | Page | Palo Alto | Plymouth |
| Pocahontas | Polk | Pottawattamie | Poweshiek | Ringgold |
| Sac | Scott | Shelby | Sioux | Story |
| Tama | Taylor | Union | Van Buren | Wapello |
| Warren | Washington | Wayne | Webster | Winnebago |
| Winneshiek | Woodbury | Worth | Wright | * |