Key West is a city in Monroe County, Florida, United States. The city encompasses the island of Key West, the part of Stock Island north of U.S. 1 (the Overseas Highway) (east), Sigsbee Park (north, originally known as Dredgers Key), Fleming Key (north), and Sunset Key (west, originally known as Tank Island).Key West is the county seat of Monroe County. Key West is known as the southernmost city in the Continental United States. Key West is a seaport destination for many passenger cruise ships. The Key West International Airport provides airline service. Hotels and guest houses are available for lodging. Naval Air Station Key West is an important year round training site for naval aviation due to the superb weather conditions. It is also a reason the city was chosen as the Winter White House of President Harry S. Truman.