1850 Counties of Michigan
| in area | Courts held at | Pop in 1850 | ||
| Allegan Co, MI | south west side on Lake Michigan near Kalamazoo, Black & Rabbit rivers | 700 sq miles | Allegan | 5,125 |
| Barry Co, MI | in southwest part, drained by Thornapple river | 576 sq miles | Hastings | 5,072 |
| Berrien Co, MI | SW corner, Lake MI on west, water by St Joseph & Gallon rivers | 576 sq miles | Berrien Springs | 11,471 |
| Branch Co, MI | south boundary, drained by St Joseph river | 528 sq miles | Branch Court House | 18,472 |
| Calhoun Co, MI | southern part, drained by Kalamazoo & St Joseph's rivers | 720 | Marshall | 13,162 |
| Cass Co, MI | south boundary | 528 | Cassopolis | 10,907 |
| Cheboygan Co, MI | north part of peninsula, straits of Mackinaw on the north | 300 | Duncan | not listed |
| Chippeway Co, MI | northern boundary | 7200 | Sault de St Marie | 898 |
| Clinton Co, MI | southern part, water by Grand Maple & Lookinglass rivers | 576 | De Witt | 5,102 |