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.
World War II by country
The small Panama Canal Zone was United States territory, and American forces from the U.S. Navy, U.S. Army, the USAAF (at Howard Air Force Base), and Colombian forces helped inside the Canal Zone, guarded the Panama Canal from both ends. This Canal provided the United States and its Allies with the ability to move warships and troops rapidly between the Atlantic Ocean and the Pacific Ocean. Since most of the American shipbuilding capability was on the East Coast and the Gulf of Mexico, the Canal was vital for moving new warships to the Pacific to fight the Imperial Japanese Navy