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.
Hay–Pauncefote Treaty
The Hay–Pauncefote Treaty is a treaty signed by the United States and Great Britain on 18 November 1901, as a legal preliminary to the U.S. building the Panama Canal. It nullified the Clayton–Bulwer Treaty of 1850 and gave the United States the right to create and control a canal across the Central American isthmus to connect the Pacific Ocean and the Atlantic Ocean. In the Clayton–Bulwer Treaty, both nations had renounced building such a canal under the sole control of one nation.