What was once the shortest US highway in the Pennsylvania, US 46 was first signed inside the Commonwealth in 1936.  It crossed the Delaware River on a truss bridge known as Darlington's Bridge at Delaware Station, a former railroad span that carried the Delaware, Lackawanna and Western Railroad between Pennsylvania and New Jersey.  The railroad needed to build a new crossing that could support heavier and larger train cars and locomotives that were starting to become commonplace around the early 20th Century, which it did just upriver.  As soon as the new crossing was completed, the DL&WRR put their old bridge on the market which was purchased by the Reverend Doctor Henry V. B. Darlington, a local Episcopal minister, for $5,000.

The reverend proceeded to replace the tracks with a roadway deck and built approaches to his new purchase.  Two buildings were constructed on the New Jersey side:  one for toll collection and the other for living quarters for the toll collector.  The toll to cross the Delaware was only a quarter.

During the 1920s and 1930s, Pennsylvania and New Jersey began purchasing bridges along the Delaware River under the Joint Commission for the Elimination of Toll Bridges.  Darlington balked at the low amount initially offered by the commission to purchase the bridge, and raised the selling price to $275,000.  The commission agreed to that price and took ownership in 1933.  Their first order of business was to remove the tolls.

Map showing the path of US 46 in Pennsylvania from 1941 Map showing the path of US 46 in Pennsylvania from 1943
The route of US 46 in the early 1940s.  (Pennsylvania Department of Highways (left) and USGS (right))

The beginning of the end for US 46 in Pennsylvania commenced in 1952 when both the Pennsylvania Department of Highways and the State Highway Department of New Jersey petitioned the American Association of State Highway Officials to change its routing.  Both agencies requested the change in conjunction with the move of the US 611 designation to the east shore of the Delaware River between Portland and Delaware Water Gap.  The reason for the change was construction of the Portland-Columbia and Delaware Water Gap toll bridges by the Delaware River Joint Toll Bridge Commission, New Jersey's desire to connect both with a four-lane, divided highway which eventually would become part of Interstate 80, and the planned removal of Darlington's Bridge at Delaware Station.  AASHO's Route Numbering Committee approved the elimination of US 46 in Pennsylvania at their meeting on December 8, 1952 in Kansas City, Missouri, with the Executive Committee following suit with their approval at their meeting the following day.

Once both bridges were opened to traffic in December 1953, US 46's alignment was changed making it an intrastate US route which it is to this day.  The DRJTBC closed Darlington's Bridge at Delaware Station on April 3, 1954 and subsequently demolished it soon after.

Western Terminus: US 611 at State Street in Portland
Eastern Entrance: New Jersey state line at the Darlington's Bridge at Delaware Station two miles east of Portland
Length: 1.93 miles
Names: Delaware Avenue and River Road
LR Designation: 517
County: Northampton
Multiplexed Routes: None
Expressway: None
Former Designations: PA 32 (1927 - 1928)
PA 987 (1928 - 1936)
Decommissioned: 1952
Replaced By: None
Links: End of US Highway 46 - Dale Sanderson