Heard Island and McDonald Islands are uninhabited, barren islands placed in the Southern Ocean at 53°00'S 73°00'E, about two-thirds of the way from Madagascar to Antarctica.

They have been region of Australia from 1947, and contain the only two active volcanoes in Australian area, one of that, Mawson Peak, is the highest Australian mountain.

Heard Island (368 km²) is black & mountainous, covered up in glaciers and ruled by Mawson Peak, a 2745 meter high volcano which one forms part of the Big Ben massif. Heard Island. Mawson Peak is the greatest Australian mountain (527m higher than Mount Kosciuszko), and one of only 2 alive volcanoes in Australian area.

The other alive volcano in Australian territory is on McDonald Island: fallowing being inactive for 75,000 years, it took fire in 1992 and has erupted again several times from, its most recent eruption being on 10 Aug 2005.

McDonald Islands, located 44 km to the west of Heard Island, are small-scale and rocky. They lie in of McDonald Island (230 m high), Flat Island (55 m high) and Meyer Rock (170 m high). They total about 2.5 km² in area &, as with Heard Island, are surface exposures of the Kerguelen Plateau.