Guantanamo Bay Naval Base, officially known as Naval Station Guantanamo Bay or NSGB, is a United States military base located on 45 square miles (117 km2) of land and water on the shore of Guantánamo Bay at the southeastern end of Cuba. It has been leased to the United States with no end date since 1903 as a coaling station and naval base, making it the oldest overseas U.S. naval base. The lease was $2,000 in gold per year until 1934, when the payment was set to match the value of gold in dollars; in 1974, the yearly lease was set to $4,085.

Guantánamo Bay is a bay in Guantánamo Province at the southeastern end of Cuba. It is the largest harbor on the south side of the island and it is surrounded by steep hills which create an enclave that is cut off from its immediate hinterland.