Between the hamlet of Mumford and the village of Scottsville, Route 16 followed Scottsville–Mumford Road. By 1919, Route 15 was extended northeast from Caledonia to meet Route 16 in Scottsville. Within the village, it was routed on River Road and Main Street. On March 1, 1921, Route 16 was truncated to end in Le Roy while the portion of its former routing north of Caledonia became part of a realigned and extended Route 15. None of Route 15 between Mumford and Scottsville was assigned a designation when the first set of routes in the modern state highway system were assigned in 1924. The portion of former legislative Route 15 from Mumford to Scottsville and the segment of pre-1921 legislative Route 15 on Main Street in Scottsville was designated as the westernmost portion of NY 253, a highway extending from Mumford to Henrietta, as part of the 1930 renumbering of state highways in New York. In Scottsville, NY 253 was concurrent with NY 35, a route stretching from Buffalo to Ontario via Canawaugus (west of Avon), Rochester, and Walworth, on Rochester Street. U.S. Route 20 was rerouted to follow NY 35 between Buffalo and Avon . As a result, NY 35 was reconfigured south of Scottsville to follow the routing of NY 253 to Mumford instead, where it ended at NY 36. NY 253 was then truncated to the former northern terminus of its overlap with NY 35 northeast of Scottsville. The NY 35 designation was split into two designations in the early 1940s, with the portion from Mumford to Ontario Center Road in Walworth becoming NY 383. The new route also continued southward for another to NY 5 in Caledonia by way of an overlap with NY 36; however, this extension was eliminated by 1970. Within Rochester, NY 383 was initially routed on Scottsville Road, Elmwood and Plymouth avenues, Main Street, and Winton Road. At the junction of Winton and Blossom roads, NY 383 turned east to follow Blossom into Penfield. It veered east upon intersecting Browncroft Boulevard to follow modern NY 286 east to Walworth. The portion of NY 383 east of NY 96 (East Avenue) in downtown Rochester became NY 286 on January 1, 1949. At the same time, NY 383 was truncated to the junction of Plymouth Avenue and Main Street in Rochester. NY 383 was further truncated to an interchange with the newly constructed Inner Loop