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
A project to build a third set of locks for the Panama Canal A was overwhelmingly approved in a referendum (with low voter turnout, however) on October 22, 2006. The official estimated cost of the project is US$5.25 billion, but the canal is of major economic importance because it provides millions of dollars of toll revenue to the national economy and provides massive employment. Transfer of control of the Canal to the Panamanian government completed in 1999, after 85 years of US control.