The seven-mile-long Alexandria Canal system linking Alexandria to Georgetown was begun in 1834 and completed in 1843. The Alexandria Canal’s Tide Lock No. 4 and adjacent holding basin, the only remaining portions of the city’s canal system, are relics of Virginia’s industrial and transportation history, being part of a waterway that helped to bring on the economic regeneration of Alexandria in the mid-19th century. The canal, which remained in operation until 1886, connected Alexandria with the Chesapeake and Ohio Canal running inland to Cumberland, Maryland. It was used largely for transporting coal. The Alexandria Canal Tide Lock and basin had long been filled in but were restored late in the 20th century as a point of interest in the city’s waterfront park development.