United States territorial acquisitions
The Panama Canal Zone was an unorganized US territory located within the Republic of Panama. It was established under the Hay–Bunau-Varilla Treaty in 1903 and disestablished in 1979 under the Torrijos–Carter Treaties. Panama gained full control over the Panama Canal in 1999.
History of the Panama Canal
After construction, the canal and the Canal Zone surrounding it were administered by the United States. On September 7, 1977, US President Jimmy Carter signed the Torrijos-Carter Treaty setting in motion the process of transferring control of the canal to Panama. The treaty became effective on October 1, 1979, providing for a 20-year period in which Panama would have increasing responsibility for canal operations before complete US withdrawal on December 31, 1999. Since then, the canal has been administered by the Panama Canal Authority (Autoridad de Canal de Panama, or ACP).