On August 1, 1979, maintenance of NY 12E between Bridge Street in Brownville and the Watertown city line was transferred from the state of New York to Jefferson County as part of a larger highway maintenance swap between the two levels of government. In return, the state assumed maintenance of Bridge Street in Brownville and the town of Hounsfield, among other highways. Following the swap, the segment of NY 12E between Bridge Street and the Watertown city limits became concurrent with CR 190 while Bridge Street became NY 971H, an unsigned reference route. The section of NY 12E within the city of Watertown was locally maintained.