In the mid-1960s, the portion of I-81 north of Watertown opened to traffic. One of the interchanges along the new highway was located east of La Fargeville, where I-81 met NY 181's former routing. As a result, NY 411 was extended westward to La Fargeville over NY 181's former alignment. NY 411 became concurrent with NY 26 through Theresa and with NY 37 west of the village as part of the extension. NY 26 was truncated to West Carthage in the mid-1970s. Its former routing from Antwerp to Alexandria Bay was then redesignated as NY 283.