Panama Canal
Colombia, France, and later the United States controlled the territory surrounding the canal during construction. The US continued to control the canal and surrounding Panama Canal Zone until the 1977 Torrijos–Carter Treaties provided for handover to Panama. After a period of joint American–Panamanian control, in 1999, the canal was taken over by the Panamanian government. It is now managed and operated by the government-owned Panama Canal Authority.
United States territory
From July 8, 1947, until October 1, 1994, the United States administered the Trust Territory of the Pacific Islands, but the Trust ceased to exist when the last member state of Palau gained its independence to become the Republic of Palau. The Panama canal, and the Canal Zone surrounding it, was territory administered by the United States until 1999, when control was relinquished to Panama.