1850 Counties of Maine
| County | Description | Area in sq miles | Courts held at | Pop in 1850 |
| Aroostock | northeast part, on westerly side of St John's river. crossed by Aroostock & Matawamkeg rivers. North part unsettled | not listed | Conway | 12,529 |
| Cumberland | southwest part, Atlantic ocean on southeast, water by Saco, Androscoggin & Kennebec rivers | 990 | Portland | 77,549 |
| Hancock | south eastern part on Atlantic ocean, Penobscot river & bay on west | 1850 | Castine | 34,372 |
| Kennebec | southern part, cross by Kennebec river | 1050 | Augusta (Capital) | 62,520 |