Constructed around 1817, the Toll House sheltered the toll keeper and stored tolls collected from travelers crossing the Susquehanna River bridge, and a window in the porch wall allowed boats coming down the canal to be spotted as bridge traffic passed. The bridge was washed away in 1856, ending the need for a toll keeper. The Susquehanna and Tidewater Canal ran from Havre de Grace, Maryland, to Wrightsville, Pennsylvania, 45 miles away. Opened in 1840, it was 15 to 20 feet wide and 6 to 12 feet deep. Its 29 granite locks, each 150 feet long and 18 feet wide, raised the water level from 20 feet in Havre de Grace to 1000 feet above sea level at Wrightsville. Nine locks were in Maryland, including three in the park. Boats were pulled by mules into a lock, where gates enclosed them and the water rose to the needed height. A flood in 1889 put the canal out of service for several weeks, and over time its use gradually declined.