1850 Counties of Wisconsin
| County | Description | Area in sq miles | Courts held at | Pop in 1850 |
| Brown | northeast part, intersected by Depere | 1150 | Green Bay | 6,215 |
| Calumet | eastern part, east side of Lake Winnebago | 300 | Pequot | 1,743 |
| Chippewa | northern part, on NW side of Mississippi river & crossed by Chippewa river | blank | not listed | 615 |
| Columbia | towards the south, crossed by Wisconsin river | blank | De Korra | 9,565 |
| Crawford | western boundary between Mississippi & Wisconsin rivers | blank | Prairie du Chien | 2,498 |
| Dane | southern part, Wisconsin river on northwest side ad contains the "Four Lakes" | 1234 | Madison (also State Capital) | 9,366 |
| Dodge | eastern part | 756 | not listed | 3,892 |
| Fond Du Lac | eastern part, Lake Winnebago on the north | 400 | Fond Du Lac | 2,024 |
| Grant | southwest corner, Mississippi river on southwest, Wisconsin river on northwest | not listed | Lancaster | 9,107 |
| Greene | southern boundary | 576 | Monroe | 6,179 |
| Iowa | south western part, Wisconsin river on north | 1300 | Mineral Point | 5,672 |
| Jefferson | southeast part, crossed by Rock river | 576 | Jefferson | 6,955 |
| Kenozha | southeast corner on Lake Michigan | blank | Kenozha | 10,734 |
| Lafayette | south boundary | blank | blank | 11,531 |