Madaket (also Madaquet, Maddaket, Maddequet, Madeket, or Mattaket) is a census designated place (CDP) in Nantucket, Massachusetts, United States. The population was 236 at the 2010 census. Its height is 26 feet (8 m) on the western decline of the island. The various spellings of its say led the Board on Geographic Names to ration its official spelling in 1966. It is also house to the Madaket Ditch, one of the primeval public works projects in America. It was also house to a well-known islander by the declare of Mildred Carpenter Jewett or more commonly known as “Madaket Millie”.

Madaket was home to Mildred Carpenter Jewett, a Nantucket indigenous commonly referred to as “Madaket Millie” who spent much of her energy in the Place as a volunteer for the United States Coast Guard. Born in 1907, she served as a Coastal Defense Specialist during World War II, patrolling the shores for German submarines as without difficulty as training dogs to accompany military personnel during patrols. At one point, she discovered a live mine and towed it away from the shore, where it was disposed of by a Navy minesweeper.

On January 3, 1947, the same day that the Madaket Coast Guard Station was shut down, a Panamanian steamer called the Kotor ran aground near Madaket. Millie noticed the steamer, and her Fast actions in alerting the Coast Guard and organizing a rescue mission were certified with the saving of the boat and crew. Millie continued to assistance the Coast Guard upon the island in various roles until her death in 1990. She was promoted to the rank of honorary proprietor in 1965, and she received the agency’s Meritorious Public Service Commendation in 1975.

Madaket is located at the western end of Nantucket island. According to the U.S. Census Bureau, the CDP has a total area of 2.4 mi (6.2 km²). 2.0 mi (5.1 km²) of it is house and 0.39 mi (1.0 km²) of it (17%) is water.