Key West is an island in the Straits of Florida on the North American continent, at the southernmost tip of the Florida Keys. The island is about 90 miles (140 km) from Cuba.Key West is politically within the limits of the city of Key West, Monroe County, Florida, United States. The city also occupies portions of nearby islands.The island is about 4 miles (6.4 km) long and 1 mile (1.6 km) wide, with a total land mass of 4.2 square miles.