Location
The subantarctic island group of Heard Island and McDonald Islands (HIMI) is located in the southwest Indian Ocean at about 53°S, 73°30’E.
The islands are around 4,100 kilometres southwest of Perth, Western Australia, 4,700 kilometres southeast of Africa and 1,000 kilometres north of Antarctica.
The nearest land is the French territory of Îles Kerguelen, an archipelago of islands around 450 kilometres to the northwest. Download a map below to see the location of HIMI relative to Australia, Antarctica and Îles Kerguelen.
While not the most isolated island in the Southern Ocean, Heard Island has seen fewer visits and fewer disturbances by humans compared with other subantarctic islands.
Heard Island and the McDonald Islands lie in the ‘furious 50s’. 18th century sailors named the area around 50 degrees south latitude for the persistently strong winds characteristic of the Southern Ocean. South of the roaring 40s and north of the screaming 60s, the persistently poor weather, high seas and vast expanses of ocean resulted in the late discovery of the islands.
The Heard Island and McDonald Islands (HIMI) Marine Reserve covers an area of approximately 380,000 square kilometres. The boundaries of the marine reserve include Heard Island and the McDonald Islands. The boundaries and zoning expanded in 2024 come into effect on 24 January 2025.
Geography
Heard Island is approximately 40 kilometres long from the western tip of the Laurens Peninsula to the eastern tip of Alert Island. It is 20 kilometres from Saddle Point on the north coast to Long Beach on the south coast. The island covers 368 square kilometres. The landscape is dominated by Big Ben, an active volcano of 2,745 m elevation.
Volcanic activity has been observed at Heard Island since the mid 1980s, with fresh lava flows on the southwest flanks of the island. Recent volcanic activity has dramatically altered the McDonald Islands, approximately 40 kilometres west of the Laurens Peninsula. Sometime during the 1990s, the main island has doubled in size and increased in elevation, resulting in the complete loss of all vegetation on the island.
Heard Island and the McDonald Islands lie south of the Antarctic Convergence, the marine zone where the colder waters of the Antarctic (surface temperatures of around 2°C) converge with, and sink under the slightly warmer (surface temperatures of around 5°C) waters of the subantarctic. Lying south of the Antarctic Convergence and surrounded by Antarctic waters, approximately 70% of Heard Island is permanently covered in glaciers with isolated vegetated headlands emerging between glaciers.
The few islands in the Southern Ocean are biological hot spots characterised by very high numbers of breeding and non-breeding seabirds and marine mammals. Vast colonies of penguins and petrels co-occur with harems of elephant seals and fur seals on the islands and forage in the surrounding ocean.