Charles River Bicycle and Walking Path Galen St & Watertown St, Watertown, MA02472 This path winds along the leafy banks of the Charles River through much of Watertown. Walkers, runners, cyclists…More and even in-line skaters can be found on the paved paths that go along both sides of the river. This trail also includes boardwalk areas and platforms to observe wildlife. It can be accessed from numerous spots, including Watertown Square and Greenough Boulevard at Arsenal Street. The path continues into Cambridge to the east and Newton to the west.