Answer Wiki. United States Naval Station Guantanamo Bay (also called Gitmo or GTMO) is located on 45 square miles (120 km2) of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling (fueling) station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba.