In the early 1970s, construction began on the Southern Expressway, a limited-access highway connecting Buffalo to Springville. The first segment of the expressway—between the New York State Thruway east of Lackawanna and US 20A west of Orchard Park—opened to traffic by 1973 as a realignment of US 219. In between the end of the expressway and North Boston, US 219 temporarily overlapped US 20A and NY 277. The former routing of US 219 from North Boston to Hamburg was redesignated as NY 391 in June 1971.
