National Historic Site (NHS) and National Historical Park (NHP) are designations for officially recognized areas of national historic significance in the United States. They are usually owned and managed by the federal government. An NHS usually contains a single historical feature directly associated with its subject, while an NHP is an area that generally extends beyond single properties or buildings to include a mix of historic and later structures and sometimes significant natural features.

Saint Croix Island, long known to locals as Dochet Island, is a small uninhabited island in Maine near the mouth of the Saint Croix River that forms part of the Canada–United States border separating Maine from New Brunswick. The island is in the heart of the traditional lands of the Passamaquoddy people who, according to oral tradition, used it to store food away from the dangers of mainland animals. The island was the site of an early attempt at French colonization by Pierre Dugua, Sieur de Mons in 1604. In 1984 it was designated by the United States Congress as Saint Croix Island International Historic Site. There is no public access to the island, but there is a visitor contact station on the U.S. mainland and a display on the Canadian mainland opposite the island.