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
The US intent to influence the area, especially the Panama Canal's construction and control, led to the separation of Panama from Colombia in 1903 and its establishment as a nation. When the Senate of Colombia rejected the Hay–Herrán Treaty on January 22, 1903, the United States decided to support and encourage the Panamanian separatist movement