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.
Panama
A project to build a third set of locks for the Panama Canal A was overwhelmingly approved in a referendum (with low voter turnout, however) on October 22, 2006. The official estimated cost of the project is US$5.25 billion, but the canal is of major economic importance because it provides millions of dollars of toll revenue to the national economy and provides massive employment. Transfer of control of the Canal to the Panamanian government completed in 1999, after 85 years of US control.