The Cape Cod National Seashore (CCNS), created on August 7th, 1961 by President John F. Kennedy, encompasses 43,500 acres (176 km²) of ponds, woods and beachfront on Cape Cod, Massachusetts. The CCNS includes nearly 40 miles (60 km) of seashore along the Atlantic-facing eastern edge of Cape Cod, in the towns of Provincetown, Truro, Wellfleet, Eastham, Orleans and Chatham.

The CCNS is run by the National Park Service, with the dual goal of protecting precious, ecologically fragile land, while allowing the public to enjoy a unique resource.

Notable sites encompassed by the CCNS include Marconi Station , site of the first two-way transatlantic radio transmission.