In the 1930 renumbering of state highways in New York, NY 3 was rerouted to exit Watertown to the east on its modern alignment. The former alignment of NY 3 from Watertown to Clayton was redesignated as NY 12E. At the same time, an alternate route of NY 12E extending from the modern junction of NY 12E and NY 180 to downtown Watertown along the northern bank of the Black River was designated as NY 12F. The alignments of NY 12E and NY 12F east of what is now NY 180 were swapped , placing both routes on their current alignments.