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 |
| Lincoln | southern boundary, on Atlantic ocean, crossed by Kennebec river | 950 | Wiscasset | 74,878 |
| Oxford | west boundary, crossed by Androscoggin, Oxford & Cumberland canal | 1600 | Paris | 39,763 |
| Penobscot | central part, crossed by Penobscot river | 3282 | Bangor | 64,089 |
| Piscataquis | central part, Moosehead lake on west | blank | Dover | 14,735 |
| Somerset | northwest boundary, crossed by Kennebec river, Moosehead or Umbagog lake on east | 3600 | Norridgewock | 35,581 |
| Waldo | in south part, Penobscot river & bay on southeast | 812 | Belfast | 47,129 |
| Washington | at southeast corner, Atlantic ocean on southeast, St Croix river & Passamaquoddy bay on northeast, Schoodie lake toward north | 3500 | Machias | 38,113 |
| York | at southwest corner, Atlantic ocean on southeast, Salmon Falls & Piscataqua rivers on southwest | 818 | Alfred & York | 60,106 |