The Tide Lock is the only remaining feature of the Alexandria Canal, built between 1834 and 1843 to link the Potomac River port with Georgetown. It was restored in 1985 in a riverfront development project. The Alexandria Canal Tide Lock is a reminder of the city’s role in American commercial history. The 7-mile-long canal joined Alexandria, a major 19th-century port, with the Chesapeake and Ohio Canal at Georgetown, another vital commercial center and an early gateway to the western frontier. In operation until 1886, the Alexandria Canal was used largely for transporting coal, the primary industrial fuel of the day.