Madaket (also Madaquet, Maddaket, Maddequet, Madeket, or Mattaket) is a census designated place (CDP) in Nantucket, Massachusetts, United States.

It was also home to a famous islander by the name of Mildred Carpenter Jewett or more commonly known as "Madaket Millie".

[6] At one point, she discovered a live mine and towed it away from the shore, where it was disposed of by a Navy minesweeper.

Millie noticed the steamer, and her quick actions in alerting the Coast Guard and organizing a rescue mission were credited with the saving of the ship and crew.

She was promoted to the rank of honorary officer in 1965, and she received the agency's Meritorious Public Service Commendation in 1975.