The Panama Canal Zone (Spanish: Zona del Canal de Panamá), was a 553 square miles (1,430 km2) territory inside of Panama, consisting of the Panama Canal and an area generally extending 5 miles (8.1 km) on each side of the centerline (but excluding Panama City and Colón, which otherwise would have fallen in part within the limits of the Canal Zone.) Its border spanned two of Panama's provinces and was created on November 18, 1903 with the signing of the Hay-Bunau Varilla Treaty. When artificial lakes were created to assure a steady supply of water for the locks, those lakes were included within the Zone. The zone consisted of the canal and an area generally extending five miles (8.0 km) on each side of the centerline, excluding Panama City and Colón, which otherwise would have been partly