The Glen Gardner Pony Pratt Truss Bridge is a historic pony Pratt truss bridge on School Street (formerly Mill Street) crossing the Spruce Run in Glen Gardner of Hunterdon County, New Jersey. It was designed by Francis C. Lowthorp and built in 1870 by William Cowin of Lambertville, New Jersey. The bridge was added to the National Register of Historic Places on September 22, 1977 for its significance in engineering, industry and transportation. It is one of the few early examples of iron Pratt truss bridges remaining in the United States. It was later documented by the Historic American Engineering Record in 1991.

The Glen Gardner bridge is one of three remaining composite cast iron and wrought iron Pratt truss bridges built by Cowin in New Jersey. The others are the New Hampton Pony Pratt Truss Bridge (1868) in New Hampton and the Main Street Bridge (1870) in Clinton. The single-span bridge is 84 feet (26 m) long and 16.6 feet (5.1 m) wide. It features a pedestrian walkway with a decorative cast-iron railing.

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  View looking east
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  View looking west
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  Railing detail, looking north

• National Register of Historic Places listings in Hunterdon County, New Jersey
• List of bridges documented by the Historic American Engineering Record in New Jersey
• List of bridges on the National Register of Historic Places in New Jersey

• Media related to Glen Gardner Pony Pratt Truss Bridge at Wikimedia Commons
• Historic American Engineering Record (HAER) No. NJ-92, "Glen Gardner Bridge, Spanning Spruce Run, Glen Gardner, Hunterdon County, NJ", 15 photos, 1 color transparency, 3 data pages, 2 photo caption pages
• School Street Bridge at Structurae