Washington Island lies about 7 miles (11 km) northeast of the tip of Door Peninsula in Door County, Wisconsin. The island has a year-round population of 708 people according to the 2010 census. It has a land area of 60.89 km² (23.51 sq mi) and comprises over 92 percent of the land area of the town of Washington, as well as all of its population. The unincorporated community of Detroit Harbor is situated on the island. It is the largest in a group of islands that includes Plum, Detroit, Hog, Pilot, Fish, and Rock Islands. These islands form the Town of Washington. Detroit Harbor bay is on the south side of the island. A large part of Washington Island's economy is based on tourism.
Washington Island is approximately 5 miles (8 km) wide by 6 miles (10 km) long. Together with the Door Peninsula, Washington Island forms a treacherous strait that connects Green Bay to the rest of Lake Michigan. Early French explorers named this water way, now littered with shipwrecks, Porte des Morts, which literally means "Door of the Dead" or, more colloquially, "Death's Door", giving both Door County and Door Peninsula their names.