Island off Cape Cod is a term used to refer to two of the most popular islands in Massachusetts: Nantucket and Martha's Vineyard. Nantucket is an island located 30 miles south of Cape Cod and is known for its whaling history, cobblestone streets, and lighthouses. Martha's Vineyard is an island located south of Cape Cod and is known for its beaches, seafood, and quaint towns. Both islands are popular tourist destinations and offer a variety of activities for visitors.