The Territory of Heard Island and McDonald Islands (HIMI) is an Australian territory that includes a group of mostly barren volcanic islands in the Antarctic region. These islands are located about two-thirds of the way between Madagascar and Antarctica. The total land area of the islands is 372 square kilometers (144 square miles), and they have a coastline of 101.9 kilometers (63 miles). The islands were discovered in the mid-1800s and became part of Australia in 1947. They are located on the Kerguelen Plateau in the southern Indian Ocean.

Heard Island and McDonald Islands are home to Australia’s only two active volcanoes. One of the volcanoes, Mawson Peak, is taller than any other mountain in all other Australian states, territories, or claimed areas except Dome Argus, Mount McClintock, and Mount Menzies in the Australian Antarctic Territory. This territory is a land claim not recognized by most other countries. Therefore, Mawson Peak is the highest mountain with clear Australian ownership.

These islands are among the most remote places on Earth. They are located about 4,100 kilometers (2,500 miles) southwest of Perth, 3,850 kilometers (2,390 miles) southwest of Cape Leeuwin, Australia, 4,200 kilometers (2,600 miles) southeast of South Africa, 3,830 kilometers (2,380 miles) southeast of Madagascar, 1,630 kilometers (1,010 miles) north of Antarctica, and 450 kilometers (280 miles) southeast of the Kerguelen Islands, which are part of the French Southern and Antarctic Lands.

The islands have no permanent residents and can only be reached by sea. A trip to visit them from Australia usually takes about two weeks.

History

In 1833, Peter Kemp, a British sailor, saw Heard Island while on the sealing ship Magnet. However, there is not enough proof that the land Kemp saw was actually Heard Island. Later, a part of Antarctica was named "Kemp Land" in his honor.

In 1853, an American sailor named John Heard, who was on the ship Oriental, spotted Heard Island while traveling from Boston to Melbourne. He reported the discovery one month later, and the island was named after him. His wife, Fidelia Heard, wrote the first detailed description of the island and made drawings of it. Six weeks later, in January 1854, William McDonald, who was on the ship Samarang, discovered the nearby McDonald Islands.

No one landed on the islands until March 1855, when American sealers from the ship Corinthian, led by Erasmus Darwin Rogers, arrived at a place called Oil Barrel Point. From 1855 to 1882, many American sealers lived on the island for one year or more. They lived in unpleasant conditions in dark, smelly huts at Oil Barrel Point. Australian sealers also used the island, including James William Robinson’s 1858 expedition for Tasmanian merchant William Crowther. Robinson’s account of the expedition, stored in the W. L. Crowther Library, is one of the most detailed records of life on the island during that time. At its peak, the island had a population of 200 people. By 1877, sealers had hunted most of the seals to extinction and left the island. During this period, the islands produced more than 16,000 cubic meters (4.3 million US gallons) of elephant seal oil.

Many shipwrecks have happened near the islands. There is also an abandoned building from John Heard’s sealing station near Atlas Cove. In 1880, the crew of the ship Trinity spent 15 months on Heard Island after their ship wrecked until they were rescued in 1882.

In April 1910, the Australian ship Wakefield briefly visited Heard Island during a search for the missing ship SS Waratah, which disappeared in 1909. In June 1910, a group from the whaling ship Mangoro claimed Heard Island for the United Kingdom. The French consul in Durban, South Africa, protested this claim, stating the island belonged to France.

In the 1920s, a South African company called the Kerguelen Whaling and Sealing Company returned to Heard Island for sealing. Around this time, the British Admiralty ordered sealers to build a small wooden hut at Atlas Cove.

In November 1947, the Australian government announced plans for the Australian National Antarctic Research Expeditions, led by Stuart Campbell, a former Royal Australian Air Force officer. Prime Minister Ben Chifley stated that the expeditions would establish weather stations on Heard Island and Macquarie Island, as well as a fuel base on the French territory of Kerguelen Island, as part of efforts to create a permanent Australian base in Antarctica.

Campbell’s team landed at Atlas Cove on December 17, 1947, setting up a base for 14 scientists. A flag-raising ceremony was held on December 29, 1947. In response, the U.S. Department of State said in January 1948 that it did not recognize Australia’s claim to the island, as it considered the area part of Antarctica and did not support claims by other countries.

In February 1951, the Australian government confirmed that the British government had given up any previous claims to Heard Island and the McDonald Islands, effective December 26, 1947.

Australians occupied a station at Atlas Cove from 1947 to 1955. The first group arrived in December 1947 and stayed until February 1949. In 1952, two members of a wintering party died while returning to their hut: radio operator Richard James Hoseason was swept out to sea, and dog trainer Alastair Graham Forbes was rescued but later died trying to return to the base. In 1969, American scientists used the station, and in 1971, French scientists expanded it. Another station was built in 1971 at Williams Bay on McDonald Island. Later expeditions used a temporary base at Spit Bay, such as in 1988, 1992–1993, and 2004–2005.

Between 1965 and 2000, at least five private expeditions visited Heard Island. Amateur radio operators have also visited the island, often with scientific teams. The first such activity was in 1947 by Alan Campbell-Drury. Two amateur radio expeditions occurred in 1983 using callsigns VK0HI (Anaconda expedition) and VK0JS and VK0NL (Cheynes II expedition). A third operation took place in 1997 (VK0IR). In 2016, a DXpedition (VK0EK) organized by Cordell Expeditions made over 75,000 radio contacts. The first aircraft landing on McDonald Island was by Australian scientists Grahame Budd and Hugh Thelander on February 12, 1971, using a helicopter. The DX code for Heard Island is 111.

Mawson Peak, located on Big Ben, was first climbed on January 25, 1965, by members of the Southern Indian Ocean Expedition (sometimes called the Patanela expedition). A second climb was made in 1983 by members of the Anaconda expedition. In 1986, an Australian National Antarctic Research Expeditions (ANARE) team landed at the summit by helicopter. In 2000, an Australian Army team completed the third climb.

In 1991, the islands were the site of the Heard Island feasibility test, an experiment to send low-frequency sound signals across the ocean. The U.S. Navy used motor vessels MV Cory Chouest and Amy Chouest to transmit signals, which were detected as far as the 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 over 20 years.

Administration, economy and defence

The islands, known as the Territory of Heard Island and McDonald Islands, are part of Australia. They are managed from Hobart by the Australian Antarctic Division, which is part of the Australian Department of Climate Change, Energy, the Environment, and Water. The territory is governed by the Heard Island and McDonald Islands Act 1953. This law places the territory under the authority of the Supreme Court of the Australian Capital Territory. The laws that apply to the territory include non-criminal laws from the Australian Capital Territory and criminal laws from the Jervis Bay Territory. The islands are covered by a marine reserve that spans 65,000 square kilometers. They are mostly visited for research, and there are no permanent human residents.

After sealing ended, the only resource used from the islands is fish. The Australian government allows limited fishing in the surrounding waters.

There are no active military bases or defense personnel on the islands. However, as part of Operation Resolute, the Royal Australian Navy and Australian Border Force use Cape and Armidale-class patrol boats to conduct maritime security operations in both mainland and offshore Australian territories, including the Heard and McDonald Islands. As of 2023, the Royal Australian Navy is replacing its Armidale-class boats with larger Arafura-class offshore patrol vessels.

Although the islands have no population, they are assigned the country code HM in the ISO 3166-1 standard. This is why the islands have the Internet domain .hm. The time zone of the islands is UTC+5.

In April 2025, the United States imposed a 10% tariff on goods from the islands as part of a new trade policy targeting its partners. This action received widespread media attention, even though the islands are uninhabited. The United States claimed it had a trade deficit with the islands, but this was based on incorrect trade data. An analysis by The Guardian found that some shipments were mistakenly labeled as coming from the islands instead of their actual countries of origin. According to World Bank data, the United States imported $1.4 million (approximately $2.23 million Australian dollars) of goods from the islands in 2022, mostly "machinery and electrical" products.

Geography

Heard Island is the largest in the group. It covers 368 square kilometers (142 square miles) and has 41 glaciers. About 80% of the island is covered in ice. The Big Ben massif is the main mountain on the island. It reaches a height of 2,745 meters (9,006 feet) at Mawson Peak, the active volcanic top of Big Ben. The climb from the shore to Mawson Peak is steeper than on any other island of similar or larger size. Only seven smaller islands have steeper slopes. A July 2000 satellite image from the University of Hawaiʻi's Institute of Geophysics and Planetology showed a 2-kilometer-long (1.2-mile) and 50–90-meter-wide (160–300-foot) lava flow moving southwest from Big Ben's summit.

The much smaller McDonald Islands are 44 kilometers (27 miles; 24 nautical miles) west of Heard Island. They include McDonald Island (186 meters or 610 feet high), Flat Island (55 meters or 180 feet high), and Meyer Rock (170 meters or 560 feet high). Together, they cover about 2.5 square kilometers (0.97 square miles), with McDonald Island alone covering 1.13 square kilometers (0.44 square miles). A small group of islets and rocks, including Shag Islet, Sail Rock, Morgan Island, Drury Rock, and Black Rock, is located about 10 kilometers (6.2 miles; 5.4 nautical miles) north of Heard Island. These cover about 1.1 square kilometers (0.42 square miles).

Mawson Peak and McDonald Island are the only active volcanoes in Australian territory. Mawson Peak is also one of the highest mountains in Australia, taller than Mount Kosciuszko. However, Dome Argus, Mount McClintock, and Mount Menzies in the Australian Antarctic Territory are taller. Since Australia does not have true sovereignty over the Australian Antarctic Territory, Mawson Peak is the highest mountain under Australia's full control. Mawson Peak has erupted several times since 2013, including in May 2023. A 2016 eruption was recorded on video. Volcanic activity on Heard Island has been observed regularly since Europeans discovered it in 1853. Small lava flows occurred almost every year between 2008 and 2020. Low-level volcanic activity, such as steam plumes and lava lakes, is common. More intense activity, including large steam plumes and lava flows, has been detected by satellites. As of September 21, 2025, satellite images suggest an ongoing eruption with lava flows and mudflows.

Heard Island and the McDonald Islands have no ports or harbors. Ships must anchor offshore. The coastline is 101.9 kilometers (63.3 miles) long. Australia claims a 12-nautical-mile (14-mile; 22-kilometer) territorial sea and a 200-nautical-mile (230-mile; 370-kilometer) exclusive fishing zone around the islands.

Heard Island is a heavily glaciated, volcanic island in the Southern Ocean, about 4,000 kilometers (2,500 miles; 2,200 nautical miles) southwest of Australia. About 80% of the island is covered in ice, with glaciers extending from 2,400 meters (7,900 feet) to sea level. Due to the steep terrain, most glaciers on Heard Island are thin, averaging about 55 meters (180 feet) in depth. The glaciers on Heard Island help scientists measure how quickly glaciers are melting, which can show changes in climate.

Between 1874 and 1929, no changes in glacier size were recorded. From 1949 to 1954, noticeable changes were seen in ice formations above 1,500 meters (5,000 feet) on Big Ben's southwestern slopes, possibly due to volcanic activity. By 1963, major glacier retreat was visible below 600 meters (2,000 feet) on most glaciers, with smaller retreats observed as high as 1,500 meters (5,000 feet).

Coastal ice cliffs of Brown and Stephenson Glaciers, which were over 15 meters (50 feet) high in 1954, had disappeared by 1963, with glaciers ending 90 meters (100 yards) inland. Baudissin Glacier on the north coast and Vahsel Glacier on the west coast lost at least 30 and 60 meters (100 and 200 feet) of ice, respectively. Winston Glacier, which retreated about 1.6 kilometers (1 mile) between 1947 and 1963, is a sensitive indicator of glacier changes. Young moraines near Winston Lagoon show that Winston Glacier lost at least 90 meters (300 feet) of ice recently. Jacka Glacier on Laurens Peninsula has also shown significant retreat since 1955.

Comparing aerial photos from December 1947 and early 1980 shows glacier retreat across Heard Island. Retreat is most noticeable on the island's eastern side, where former tidewater glaciers now end inland. Glaciers on the northern and western coasts have narrowed, and glaciers on Laurens Peninsula have shrunk by 30 to 65%.

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