Glen Gardner Bridge, Spanning Spruce Run, Glen Gardner, Hunterdon County, NJ

Significance: The Old Mill Bridge is one of three composite cast- and wrought-iron Pratt truss bridges in New Jersey, and one of the few still existing in the United States. First used in the mid-nineteenth century, by 1870 the iron Pratt truss had become a common feature on the Pennsylvania Railroad and a number of its affiliates.
Survey number: HAER NJ-92
Building/structure dates: 1870 Initial Construction