The Paw Paw Tunnel is one of the major features of the canal, built as a bypass to some very difficult terrain along the Potomac River in Paw Paw Bends. Here the river makes a series of gargantuan loops; the tunnel route cutting across one large double loop takes 1 m where river takes six. While tunnel route involved cutting thru 3118' of solid rock, the Maryland shore of river route contains some impressive cliffs coming right down to the river.