Dunlap Creek Bridge

Dunlap Creek Bridge carries Market Street and State Route 4003, on the line of the old National Road, over Dunlap Creek in Brownsville, Pennsylvania. Completed in 1839 by the United States Army Corps of Engineers, it is recognized as the first cast-iron metal arch bridge in the United States. ^{1 3} The bridge stands in “The Neck,” the local name for Brownsville’s historic business district and the narrowest section of the entire National Road. ²

The bridge is a single-span, cast-iron arch-rib structure. It originally had no sidewalks and a roadway width of 23 feet 4 inches. ² In 1922, it was modified with replacement deck material, cantilevered support brackets, and sidewalks with replacement metal railings. ¹

In 1926, the road through The Neck became part of U.S. Route 40, which remained until 1962 when a bypass was completed. ² The bridge was rehabilitated in 1980.

PennDOT is now undertaking a sensitive rehabilitation intended to restore views of the historic bridge while preserving its structural integrity, stability, and soundness. The work includes a new mid-block crossing and a separate pedestrian bridge to improve safety and accessibility. ^{1 2} Project materials called for the bridge superstructure to be disassembled so repairs could be performed in a controlled environment; cast-iron members were to be repaired with braze welding, while epoxy and thin stainless-steel plates were to be used where needed to address voids and imperfections that trapped water. PennDOT also identified repairs to the stone abutments, including rotating existing stones 180° where feasible. ²

PennDOT’s plans also included removal of foundation remnants and support columns, backfilling an abandoned basement vault beneath a nearby sidewalk, and replacing portions of the creek wall. ² A companion project on the nearby Brownsville Avenue bridge that was completed before the Dunlap Creek closure, includeds removal of the asphalt riding surface, sidewalk, and barriers; repairs to the existing beams; construction of a new concrete deck, sidewalk, and barriers; installation of guide rail; and paving of the approaches from Shady Avenue to Seneca Street. That work is intended to strengthen the bridge enough to remove its weight-limit posting. ¹ PennDOT listed the combined cost of the Dunlap Creek and Brownsville Avenue bridge projects at about $9 million to $10 million, and as of its March 26, 2026, update, the cast-iron bridge had been fully disassembled for off-site cleaning, painting, and structural repairs while work continued on the abutments and the new pedestrian bridge.