1850 Counties of New York
| in area | Courts held at | Pop in 1850 | ||
| Albany Co, NY | west side of Hudson river, Mohawk on the NE | 462 sq miles | Albany | 93,279 |
| Alleghany Co, NY | south west part, crossed by Alleghany river | 1,120 sq miles | Angelica | 37,812 |
| Broome Co, NY | south boundary, crossed by Susquehanna river | 860 sq miles | Binghamton | 30,660 |
| Cattaraugus Co, NY | south boundary | 1,232 | Ellicottville | 38,950 |
| Cayuga Co, NY | western part, Cayuga lake on west, Skaneateles lake on east and Lake Ontario on north, water by Seneca river, Owasco lake & Erie canal | 648 | Auburn | 55,460 |
| Chautauque Co, NY | southwest corner, Lake Erie on NW, contains Chautauque lake | 1017 | Mayville | 50,493 |
| Chemung Co, NY | south boundary, water by Chemung river, Cayuta & Newtown creeks, Seneca lake inlet & Chemung canal | 530 | Elmira | 28,795 |
| Clinton Co, NY | northeastern part, west side of Lake Champlain | 932 | Plattsburgh | 40,048 |
| Columbia Co, NY | east boundary, with Hudson river on the west | 624 | Hudson | 43,092 |
| Cortland Co, NY | southwest of central part, crossed by Toughnioga river | 500 | Cortland | 25,140 |
| Delaware Co, NY | southeast part, Delaware river on southwest | 460 | Delhi | 39,825 |