 Much of US 4 south of Hudson Falls initially overlapped with other routes; most of the overlaps were gradually eliminated during the 1940s and 1950s as the concurrent routes were eliminated or truncated.At one time, US 4 overlapped with NY 32 from Waterford to Northumberland with no interruption in between.The concurrency was split into two shorter overlaps when US 4 was realigned in the 1950s to follow its current alignment between Bemis Heights and Schuylerville.