Construction began on a bypass of NY 17 and US 15 in the vicinity of Corning (modern exit 45) and Painted Post (exit 43). The entirety of the highway, plus an extension northwest to Campbell (exit 41), was completed between 1964 and 1968. US 15 and NY 17 were rerouted to follow the new highway, and their former routings between Campbell and Corning were redesignated as NY 415. The route also continued eastward into downtown Corning, where it ended at the junction of Pulteney Street and Baker Street (NY 414). The portion of the US 15 / NY 17 freeway between Campbell and Avoca (exit 36) was completed by 1973; however, NY 415 continued to terminate in Campbell until July 1, 1974 when it was extended north to a junction with NY 21 south of Wayland following the completion of I-390 between Avoca and Wayland. When the Corning Bypass (part of the Southern Tier Expressway) was built in 1995, NY 414 was rerouted to follow Centerway through the city. NY 415 was then extended east for two blocks to meet the new routing of NY 414.