US 219 was extended into New York , overlapping NY 75 between Ashford and Springville. The overlap with NY 75 was eliminated by 1940 when NY 75 was truncated northward to US 62 in Hamburg. In the mid-1950s, US 219 was shifted westward onto a new highway between Ellicottville and Springville; however, NY 240 was not extended south to Ashford over its former routing until the mid-1960s. In the Buffalo area, NY 240 was extended northwestward along South Park Avenue to Main Street, which carried NY 5 at the time, in the late 1930s. It was altered to follow Harlem Road across Cazenovia Creek to Seneca Street, where it ended at NY 16. NY 240 was extended northward along Harlem Road to NY 324 in Amherst in the mid-1960s. The portion of NY 240's former routing on Potter Road between the Buffalo city line and Harlem Road is now NY 950M, an unsigned reference route.