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 Panama (1821–1903)
Furthermore, the United States was entitled to acquire additional areas of land or water necessary for canal operations and held the option of exercising eminent domain in Panama City. Within this territory Washington gained "all the rights, power, and authority . . . which the United States would possess and exercise if it were the sovereign ... to the entire exclusion" of Panama.