High Quality Content by WIKIPEDIA articles! Nantucket is an island 30 miles (48 km) south of Cape Cod, Massachusetts, in the United States. Together with the small islands of Tuckernuck and Muskeget, it constitutes the town of Nantucket, Massachusetts, and the coterminous Nantucket County, which are consolidated. Part of the town is designated the Nantucket CDP, or census designated place. The region of Surfside on Nantucket is the southernmost settlement in Massachusetts.