United States Antarctic Program

United States Antarctic Program (USAP) is an organization of the United States government which has presence in the continent of Antarctica. Founded in 1959, USAP manages all U.S. scientific research and related logistics in Antarctica as well as aboard ships in the Southern Ocean.

Operation Highjump in 1946–1947 was the largest single expedition ever to explore Antarctica, involving thirteen U.S. naval vessels, numerous airplanes and more than 4,700 men. The next year, the Navy's Operation Windmill used helicopters to complete some of the work begun during Highjump,

Micronationalists
There are Micronationalists of the United States who ignore all territorial claims in Antarctica, including the British government, to claim the entire continent as their own, such as the Federated States of Antarctica.