Heard Island and McDonald Islands
The Territory of Heard Island and McDonald Islands 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 land area is and it has of coastline. Discovered in the mid-19th century, the islands lie on the Kerguelen Plateau in the southern Indian Ocean and have been an Australian territory since 1947.
Heard Island and McDonald Islands contain Australia's only two active volcanoes. The summit of one, Mawson Peak, is higher than any mountain in all other Australian states, territories or claimed territories, except Dome Argus, Mount McClintock and Mount Menzies in the Australian Antarctic Territory. This Antarctic territory is a land claim unrecognised by most other countries, meaning that Mawson Peak is the highest mountain with undisputed Australian sovereignty.
The islands are among the most remote places on Earth: They are located about southwest of Perth, southwest of Cape Leeuwin, Australia, southeast of South Africa, southeast of Madagascar, north of Antarctica, and southeast of the Kerguelen Islands.
The islands, which are uninhabited, can be reached only by sea, and typically require a two-week voyage from Australia to visit.
History
Early activities
An early sighting of Heard Island is attributed to Peter Kemp of the British sealing snow Magnet on 27 November 1833. However, the evidence that Heard Island was the land sighted by Kemp is limited. Kemp Land in Antarctica was later named in his honour.An American sailor, John Heard, on the ship Oriental, sighted Heard Island on 25 November 1853, en route from Boston to Melbourne. He reported the discovery one month later and had the island named after him. His wife Fidelia Heard provided the first written description and drawings of the island. William McDonald aboard Samarang discovered the nearby McDonald Islands six weeks later, on 4 January 1854.
No landing took place on the islands until March 1855, when American sealers from Corinthian, led by Erasmus Darwin Rogers, went ashore at a place called Oil Barrel Point. From 1855 to 1882 a number of other American sealers spent a year or more on the island, living in appalling conditions in dark smelly huts, also at Oil Barrel Point. The island was also exploited by Australian sealers, including James William Robinson's 1858 expedition on behalf of Tasmanian merchant William Crowther. Robinson's memoir of the expedition was deposited in the W. L. Crowther Library and provides one of the most detailed accounts of early conditions on the island. At its peak the community consisted of 200 people. By 1877, sealers had wiped out most of the seal population and left the island. In all, the islands furnished more than of elephant seal oil during this period.
A number of wrecks have occurred in the vicinity of the islands. There is also an abandoned building left from John Heard's sealing station that is situated near Atlas Cove. The shipwrecked crew of Trinity spent 15 months on Heard Island from the wreck in October 1880 until their rescue in January 1882.
In April 1910, the Australian-chartered steamer Wakefield briefly visited Heard Island as part of an unsuccessful search for, which had disappeared in July 1909 en route from Australia to England. In June 1910, a party from the whaling vessel Mangoro annexed Heard Island on behalf of the United Kingdom. The annexation was protested by the French consul in Durban, South Africa, on the grounds that the island was French territory.
The Kerguelen Whaling and Sealing Company, a South African enterprise, resumed sealing at Heard Island during the 1920s. Around this time the British Admiralty commissioned sealers to build a small wooden hut at Atlas Cove.
Australian administration
In November 1947, the Chifley government announced a series of Australian National Antarctic Research Expeditions under the command of Stuart Campbell, a former Royal Australian Air Force officer. Prime Minister Ben Chifley announced that the expeditions would establish weather stations on Heard Island and Macquarie Island, as well as a reserve fuel base on the French territory of Kerguelen Island, as part of a scheme to establish a permanent Australian base in Antarctica.Campbell's expedition landed at Atlas Cove on 17 December 1947, establishing a forward base for 14 scientists. Following the successful landing of all stores and equipment, a flag-raising ceremony was held on 29 December 1947. In response, the U.S. Department of State issued a statement on 4 January 1948 that it did not recognise an Australian claim to the island, as it considered it to be an Antarctic territory and did not recognise any claims from other sovereign states over the Antarctic.
In February 1951, the Australian government announced that it had received confirmation from the British government that it had relinquished any prior claim over Heard Island and the McDonald Islands, backdated to 26 December 1947.
Australians continuously occupied a station at Atlas Cove from 1947 to 1955. The first of these ventures arrived in December 1947 and stayed until February 1949. Two members of the 1952 wintering party died in May while returning to their hut: radio operator Richard James Hoseason was swept out to sea, while dog trainer Alastair Graham Forbes was rescued from the sea but died while attempting to return to the base. The camp at Atlas Cove was again occupied by American scientists in 1969 and expanded in 1971 by French scientists. Another station was established in 1971 at Williams Bay on McDonald Island in the McDonald Islands. Later expeditions used a temporary base at Spit Bay in the east, such as in 1988, 1992–1993, and 2004–2005.
There were at least five private expeditions to Heard Island between 1965 and 2000. Several amateur radio operators have visited Heard, often associated with scientific expeditions. The first activity there was in 1947 by Alan Campbell-Drury. Two amateur radio DXpeditions to the island took place in 1983 using the callsigns VK0HI and VK0JS and VK0NL, with a further operation in January 1997. The DXpedition in March 2016 was organised by Cordell Expeditions, and made over 75,000 radio contacts. The first recorded aircraft landing on McDonald Island was made by Australian scientists Grahame Budd and Hugh Thelander on 12 February 1971, using a helicopter. The DX code for Heard Island is 111.
Mawson Peak, atop Big Ben, was first climbed on 25 January 1965 by five members of the Southern Indian Ocean Expedition to Heard Island. The second ascent was made by five members of the Heard Island Expedition 1983. A helicopter landing was made at the summit by an Australian National Antarctic Research Expeditions team on 21 December 1986. An Australian Army team was successful in making the third ascent in 2000.
In 1991, the islands were the location for the Heard Island feasibility test, an experiment in very long-distance transmission of low frequency sound through the ocean. The United States Navy-chartered motor vessels and transmitted signals which were detected as far away as both ocean coasts of the United States and Canada.
In 2025, the Australian icebreaker RSV Nuyina conducted the Australian Antarctic Program's first dedicated environmental management visit to Heard Island in more than 20 years.
Administration, economy and defence
The islands are a territory of Australia administered from Hobart by the Australian Antarctic Division of the Australian Department of Climate Change, Energy, the Environment and Water. The administration of the territory is established in the Heard Island and McDonald Islands Act 1953, which places it under the jurisdiction of the Supreme Court of the Australian Capital Territory, with the non-criminal laws of the Australian Capital Territory and the criminal laws of Jervis Bay Territory applying to the Territory. The islands are contained within a marine reserve and are primarily visited for research, meaning that there is no permanent human habitation.With the end of sealing, the only exploited resource is fish; the Australian government allows limited fishing in the surrounding waters.
There are no active military installations nor defence personnel on the islands. However, as part of Operation Resolute, the Royal Australian Navy and Australian Border Force deploy and patrol boats to carry out civil maritime security operations in both Australian mainland and offshore territories including the Heard and McDonald Islands. In part to carry out this mission,, the RAN's Armidale-class boats are in the process of being replaced by larger s.
Despite the lack of population, the islands have been assigned the country code HM in ISO 3166-1, hence the Internet top-level domain.hm. The time zone of the islands is UTC+5.
In April 2025, as part of a sweeping campaign of tariffs against its trading partners, the US explicitly implemented a 10% tariff against the islands, despite the islands being uninhabited, earning the islands widespread media coverage. The US claimed it had a trade deficit with the islands, an allegation that appeared to be calculated from incorrect trade data. An analysis of US import data and shipping records by The Guardian indicated some shipments were incorrectly labelled as coming from the remote islands instead of their correct countries of origin. According to export data from the World Bank, the US imported of products from Heard Island and McDonald Islands in 2022, nearly all of which was "machinery and electrical" imports.
Geography
Heard Island, by far the largest of the group, is a mountainous island covered by 41 glaciers; 80% of the island is covered with ice. The Big Ben massif dominates the island: It has a maximum elevation of at Mawson Peak, the historically active volcanic summit of Big Ben, to which the average ascent from shore is steeper than that for any island of comparable size or larger; only seven smaller islands are steeper. A July 2000 satellite image from the University of Hawaiʻi's Institute of Geophysics and Planetology Thermal Alert Team showed an active and lava flow trending southwest from the summit of Big Ben.The much smaller and rocky McDonald Islands are located to the west of Heard Island. They consist of McDonald Island, Flat Island and Meyer Rock. They total approximately in area, where McDonald Island is. There is a small group of islets and rocks about north of Heard Island, consisting of Shag Islet, Sail Rock, Morgan Island, Drury Rock, and Black Rock. They total about in area.
Mawson Peak and McDonald Island are the only two active volcanoes in Australian territory. Mawson Peak is also one of the highest Australian mountains. It is surpassed by Dome Argus, Mount McClintock and Mount Menzies in the Australian Antarctic Territory, a territorial claim unrecognised by most other countries, meaning that Mawson Peak is the highest mountain over which Australia has true sovereignty. Mawson Peak has erupted several times since 2013 and as recently as May 2023. An earlier eruption was filmed on 2 February 2016. Volcanic activity has been regularly observed on Heard Island ever since its discovery by Europeans in 1853 producing small lava flows almost annually between 2008 and 2020, so low-level volcanic activity is frequent or perhaps even continuous. Low-level volcanic activity is punctuated by more vigorous episodes of activity that are detectable via satellite and include large vapour plumes and lava flowssatellite imagery suggests an ongoing eruption with lava effusion and mudflow as of 21 September 2025.
Heard Island and the McDonald Islands have no ports or harbours; ships must anchor offshore. The coastline is in extent, and Australia claims a territorial sea and exclusive fishing zone around the islands.