The Union Canal was a towpath canal that existed in southeastern Pennsylvania in the United States during the 19th century. First proposed in 1690 to connect Philadelphia with the Susquehanna River, it ran approximately 82 mi from Middletown on the Susquehanna below Harrisburg to Reading on the Schuylkill River.

The Susquehanna River is a major river located in the Mid-Atlantic region of the United States, overlapping between the lower Northeast. At 444 miles (715 km) long, it is the longest river on the East Coast of the United States. By watershed area, it is the 16th-largest river in the United States, and also the longest river in the early 21st-century continental United States without commercial boat traffic.