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.
Cristóbal, Colón
In 1904, after Panama's US-backed declaration of independence from Colombia, the Canal Commission set up its provisional headquarters in Cristóbal. By then, the United States had purchased the French Canal enterprise's assets in Panama and had secured use and control of the Canal Zone "in perpetuity." The Panama Railroad's assets also came under Canal Zone control, and its facilities became part of the Canal Zone town of Cristóbal.