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 Canal Department
The Isthmian Canal Commission and the Panama Canal Guard of 1904–1914 both played a pivotal role in the construction and early defense of the Canal. With the active support and encouragement of the United States, Panama declared its independence from Colombia on 3 Nov. 1903 and that same month, the United States received the right to build and administer the Panama Canal.