The C&O Canal follows the route of the Potomac River for 184.5 miles from Washington, D.C. to Cumberland, MD. The canal operated from 1828-1924 as a transportation route, primarily hauling coal from western Maryland to the port of Georgetown in Washington, D.C. Hundreds of original structures, including locks, lockhouses, and aqueducts, serve as reminders of the canal's role as a transportation system during the Canal Era. In addition, the canal's towpath provides a nearly level, continuous trail through the spectacular scenery of the Potomac River Valley. Leashed pets are allowed along the towpath and on most trails. Leashes must be no longer than six feet. Pets are not permitted in the buildings, on the boardwalk trails on the Olmsted Island Bridges and on the Billy Goat “A” Trail around Bear Island.