Cape Cod, hooked sandy peninsula of glacial origin encompassing most of Barnstable county, southeastern Massachusetts, U.S. It extends 65 miles (105 km) into the Atlantic Ocean, has a breadth of between 1 and 20 miles (1.6 and 32 km), and is bounded by Cape Cod Bay (north and west), Buzzards Bay (west), and Vineyard and Nantucket sounds (south). The Elizabeth Islands are located to the southwest, and the islands of Martha’s Vineyard and Nantucket lie to the south. The Cape Cod Canal, 17.5 miles (28 km) long, cuts across the base of the peninsula, separating it from the mainland; it shortens the shipping distance between New York City and Boston by more than 75 miles (120 km).

Cape Cod was named by Bartholomew Gosnold, an English explorer who visited its shores in 1602 and took aboard a “great store of codfish.” In 1620 the Pilgrims landed at the site of Provincetown, on the hooked tip of Cape Cod, before proceeding to Plymouth.

The cape’s climate is influenced by its overall proximity to the Atlantic Ocean and the presence of both the Gulf Stream current and the Labrador Current; the climate tends to be moderate compared with that of the mainland, with warmer winters and cooler summers. Plant life includes beach grasses, heath, and trees such as white cedar, red maple, pitch pine, and beech. Shorebirds and seabirds, such as piping plovers and terns, are abundant. The cape’s favourable climate, scenic beauty, and proximity to the Eastern Seaboard’s major urban areas have made it one of the country’s premier tourist and vacation destinations. During the summer coastal towns and villages such as Barnstable, Bourne, Chatham, Dennis, Eastham, Falmouth, Harwich, Hyannis, Provincetown, Sandwich, Truro, Wellfleet, and Woods Hole become densely populated resorts and busy fishing ports. There is a major oceanographic institution at Woods Hole, established in 1930. An airport and summer ferries link Provincetown, the northernmost town, to Boston; ferries also connect Provincetown and other points on the cape with Martha’s Vineyard and Nantucket, both also major tourist and vacation destinations. The economy of Cape Cod is boosted by Otis Air National Guard Base (in Bourne, Mashpee, and Sandwich). Limited farming produces extensive crops of cranberries as well as asparagus.

The northern and eastern sides of the cape’s hook were designated Cape Cod National Seashore in 1961. Monomoy National Wildlife Refuge is located on islands off the southeastern tip of the cape.