The Jethro Coffin House, also known as the Oldest House, is a saltbox house on Sunset Hill Road in Nantucket, Massachusetts. Built in 1686, is the oldest house on Nantucket in its original location and is the only surviving structure from the island's 17th century English settlement. Because of the brick design on its chimney, it is also called the Horseshoe House. The house was designated a National Historic Landmark in 1968. It is now a historic house museum owned and operated by the Nantucket Historical Association.