Panama Canal Zone
The Panama Canal Zone () was an unincorporated territory of the United States from 1903 to 1979, centered on the Panama Canal and surrounded by the Republic of Panama. The zone consisted of the canal and an area generally extending on each side of the centerline, excluding Panama City and Colón, which otherwise would have been partly within the limits of the Zone. Its border spanned three of Panama's provinces. When reservoirs were created to assure a steady supply of water for the locks, those lakes were included within the Zone.
List of former United States military installations in Panama
In 1903, the Hay–Bunau-Varilla Treaty was signed between Panama and the United States. It created the Panama Canal Zone as a U.S. governed region, and allowed the U.S. to build the Panama Canal. In 1977, the "Panama Canal Treaty" (also called "Torrijos–Carter Treaties") was signed by Commander of Panama's National Guard, General Omar Torrijos and U.S. President Jimmy Carter. Over time, it would replace and absolve the 1903 treaty.