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 Division
The Panama Canal Division was a unit of the United States Army, established in order to ensure the United States could adequately defend the Canal Zone in Panama. When it was authorized in 1920, similar divisions were organized to defend Hawaii and the Philippines. The division was organized in 1921, and active until 1932.