Cape Cod, Massachusetts Spring, 1997 Cape Cod and Cape Cod Bay (visible at the center of the image) can be seen in this generally west-looking view. Cape Cod is a narrow peninsula, glacial in origin that is constantly changing as winds and water move sand along the shoreline. Cape Cod extends 65 miles (105 km) east and north into the Atlantic Ocean (bottom portion of image). Parts of Cape Cod constitute the Cape Cod National Seashore, an area covering 44600 acres (18063 hectares). This area contains beaches, sand dunes, marshes, freshwater ponds, and historic sites, including the first Marconi wireless station in the United States. A portion of Nantucket Island can be seen in the upper left portion of the image.