Middlesex Canal

Running 27.25 miles from the Merrimack River at Lowell to the Charles River in Boston, the Middlesex Canal was completed in 1803, ten years after its incorporation. Planned under James Sullivan and engineered by Loammi Baldwin, it originally had twenty locks, eight aqueducts and forty-eight bridges, with the Concord River at North Billerica as its main water supply. The nomination describes it as the oldest canal of its size in the United States and a model for the Erie Canal, which New York officials came to study in 1817. Baldwin introduced hydraulic cement and the wye level to American work, and a steam tug was tried on the canal in 1812. Traffic peaked in the 1820s and 1830s, then declined after the Boston and Lowell Railroad opened in 1835. Operations ceased by 1853. Today the Shawsheen Aqueduct piers and stretches of trough and towpath survive, while much of the eastern route has been lost to development.