The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size is 372 km2 in area and it has 101.9 km of coastline. Discovered in the mid-19th century, the islands lie on the Kerguelen Plateau in the Indian Ocean and have been an Australian territory since 1947. They contain Australia's only two active volcanoes. The summit of one, Mawson Peak, is higher than any mountain in all other Australian states or territories, except Dome Argus, Mount McClintock and Mount Menzies in the Australian Antarctic Territory.
The islands are among the most remote places on Earth: They are located about 4,099 km southwest of Perth, 3,845 km southwest of Cape Leeuwin, Australia, 4,200 km southeast of South Africa, 3,830 km southeast of Madagascar, 1,630 km north of Antarctica, and 450 km southeast of the Kerguelen Islands (part of French Southern and Antarctic Lands). The islands, which are uninhabited, can only be reached by sea, which from Australia takes two weeks in the vessels normally used to access them.