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.
Panama–United States relations
The 1977 Panama Canal Treaties entered into force on October 1, 1979. They replaced the 1903 Hay–Bunau-Varilla Treaty between the United States and Panama (modified in 1936 and 1955), and all other U.S.-Panama agreements concerning the Panama Canal, which were in force on that date. The treaties comprise a basic treaty governing the operation and defense of the Canal from October 1, 1979 to December 31, 1999 (Panama Canal Treaty) and a treaty guaranteeing the permanent neutrality of the Canal (Neutrality Treaty).