Monogahela River Navigation system. One of the nation's earliest and most successful river navigation systems, its series of locks and dams, begun in 1838, has provided year-round navigation between Pittsburgh and Fairmont, WV. Millions of tons of coal shipped through the locks supplied Pennsylvania's important coke, iron, and steel industries. Acquired by the federal government in 1897, the system has been expanded and modernized by the Army Corps of Engineers.

at Elizabeth Lock & Dam, Bunola River Rd., Elizabeth, PA, United States

Elizabeth. Here were the boatyards of John and Samuel Walker, a major center for building boats for western waters. A ship launched in 1793 at these yards reached Philadelphia via New Orleans.

Between exit ramp of PA 51 and Elizabeth Bridge, Elizabeth, PA, United States