artificial waterway in southeastern Massachusetts, U.S. A part of the Atlantic Intracoastal Waterway, it joins Cape Cod Bay (northeast) with the waters of Buzzards Bay (southwest) and traverses the narrow isthmus of Cape Cod (Cod, Cape). The canal is 17.5 miles (28 km) long, including its dredged approaches. It has a width of 500 feet (152 metres) and a minimum depth of 30 feet (9 metres). There are no locks, but there are considerable tidal movements.

Begun in 1909 and put into operation in July 1914 by private capital, the canal cut the distance for waterborne traffic between New York City and Boston (via the East River, Long Island Sound, and the canal) by more than 75 miles (120 km) and also eliminated the treacherous, often windy voyage around the cape, especially through the shallows along the tip near Provincetown. The Cape Cod Canal was purchased by the U.S. government in 1927. It is operated toll free by the U.S. Army (United States Army, The) Corps of Engineers, which also maintains the canal environs for recreational use.