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 two 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.