The Territory of Heard Island and McDonald Islands is an Australian external territory in the southern Indian Ocean. Discovered in the mid-19th century, the territory is a group of sub-Antarctic volcanic islands that lie on the Kerguelen Plateau. It is about 4000 kilometres (2500 mi) south-west of the Australian mainland and 1700 kilometres (1100 mi) north of Antarctica. The territory contains Australia's only active volcanoes and is home to its highest point outside the Australian Antarctic Territory, Mawson Peak.

From Wikipedia: Heard Island and McDonald Islands · CC BY-SA 4.0