Old Mill Road Bridge

The Old Mill Road Bridge was built in 1889 and is a six panel Pratt Through Truss. The NBI lists the bridge as steel, but it is most likely wrought iron based on the construction date. Unfortunately, the bridge plaques have been lost, so the builder and exact construction date are unknown.

This bridge is an early example of an unaltered bridge with standardized details. This type of standardization became common by the 1890s, when companies switched from unique patented details to standard compositions. This created a lot more consistency between bridges, which is why there are so many similar Pratt and Parker Truss bridges in PA. However, this bridge is significant because of its lack of alterations.

This standard truss design uses eye bars for the lower chords and diagonals, built up box sections for the upper chords, and channels with lacing for the verticals. It has lattice portals with lattice brackets, and pipe railings attached to the interior faces of the trusses. The floor beams are built up and have U-shaped hangers. The wood stringers and deck were replaced in 1994, but the style mimics the original construction. The bridge is supported by fieldstone abutments.

In February of 2024, Union County and PennDOT announced a plan to spend an estimated $4.7 million on four bridges using federal, state and local funds. The proposal included $50,000 to rehabilitate or replace the Old Mill Road Bridge. The project is currently in preliminary engineering design, so there have been no official decisions about the full scope of the project. It was noted that the construction is planned for 2028.