Key West is an island in the Straits of Florida, within the U.S. state of Florida. Together with all or parts of the separate islands of Dredgers Key, Fleming Key, Sunset Key, and the northern part of Stock Island, it constitutes the City of Key West.

The Straits of Florida, Florida Straits, or Florida Strait is a strait located south-southeast of the North American mainland, generally accepted to be between the Gulf of Mexico and the Atlantic Ocean, and between the Florida Keys (U.S.) and Cuba. It is 93 mi (150 km) wide at the narrowest point between Key West and the Cuban shore, and has been sounded to a depth of 6,000 feet (1,800 m). The strait carries the Florida Current, the beginning of the Gulf Stream, from the Gulf of Mexico.