Chile is.
No. New Zealand is not the closest country. The very southern tip of Chile is the nearest point of a country to Antarctica.
The Antarctic Ocean is the closest ocean to Melbourne.
South America
The closest Caribbean country to the United States is The Bahamas. Specifically, the island of Bimini is located just about 50 miles off the coast of Florida. This proximity makes it a popular destination for U.S. travelers seeking a quick getaway to the Caribbean.
There are no countries in the Antarctic.
The mountains of the Antarctic Peninsula are considered to be a continuation of the Andes Mountains of South America.
Casey which is 3400kmsaway
The closest South American country to the United States is Colombia. The two countries are separated by the Caribbean Sea, with the distance between the U.S. and Colombia being approximately 1,200 miles at their nearest points. Colombia's proximity is highlighted by its location at the northwestern tip of South America, making it the closest point on the continent to the U.S.
No country owns any part of the Antarctic continent.
No.
The Antarctic Circle does not pass through any country.