- Southern Terminus:
- Front Street (US 11) and Castle Creek Road (US 11) in Binghamton
- Northern Terminus:
- NY 37 in Morristown
- 221.56 miles
- Broome, Chenango, Madison, Oneida, Lewis, Jefferson, St. Lawrence
NY 12 is a major north/south route extending from Binghamton to the St. Lawrence River. It begins at US 11 and runs northeast toward Utica. In New Hartford, it joins NY 5 to become the North-South Arterial Highway. NY 8 also merges in after a short distance. The three routes follow the arterial through Utica to the beginning of I-790. All four are multiplexed for one exit, after which I-790/NY 5 splits off onto the service roads of the New York Thruway (I-90). NY 8/NY 12 continues north as an expressway. After another few miles, NY 8 splits off to become a surface road. NY 12 continues north as an expressway for another couple of miles, and then the expressway ends. NY 12 runs northwest to Watertown, where it crosses I-81. It continues north to the St. Lawrence River and then turns northeast along the river. It crosses I-81 again at its northernmost interchange before the Thousand Islands. It continues to follow the river to Morristown, where it merges into NY 37.