 Pre-1927 Route 18S was designated along the portion of the current route east of McKee City in 1923, with the US 40 designation along this portion following in 1926.In 1927, Route 18S became Route 48 and Route 42 was designated along the road between Williamstown and McKee City.US 322 was extended to New Jersey in 1936, running from a ferry dock on the Delaware River in Bridgeport east to Williamstown, where it followed Route 42 and U.S. Route 40/Route 48 to Atlantic City.