Geography of Australia: Data, Water, Gondwana, Island or Continent | Sea Life, Islands and Oceania

Home | Category: Nature and Environment / Travel Information

GEOGRAPHY OF AUSTRALIA

Australia is 7,741,220 square kilometers (2,989,577 square miles) in area which is about the size of the continental United States. The sixth largest country in the world, it covers approximately 5 percent of the earth's land area. Australia is the world's smallest continent but seventh largest country. It is the only continent without glaciers and the driest inhabited continent on earth, making it particularly vulnerable to the challenges of climate change.

Australia measures about 4,025 kilometers (2,500 miles) from east to west and 3,220 (2,000 miles) from north to south. It is also the world's hollowest continent. More than 90 percent of its people live within an hour and a half of the sea and most of them live in the southeast corner of the country. The interior of the country is largely devoid of people. Australia has 25,760 kilometers (16,007 miles) of coastline, all but one major city is on the coast.

Australia contains some of the oldest rocks on Earth. In 1983, rock grains from Western Australia were dated at approximately 4.1 to 4.2 billion years old, making them the oldest known terrestrial materials discovered at that time.

National Geographic photographer Sam Abell wrote: “Just at the edge of those beautiful Australian cities, an utterly pristine landscape begins — endless empty beaches, clean sweeping ocean waters, fresh air and only 18 million people in a country the size of the 48 contiguous United States. Some cities are surrounded by truely wild lands — Perth, especially. It’s in Western Australia, one of the most uninhabited parts of the planet, and Perth itself is probabably the most isolated city on Earth, actually close to some cities in India than other cities in Australia.

Administrative Divisions: Six states and two territories: Australian Capital Territory, New South Wales, Northern Territory, Queensland, South Australia, Tasmania, Victoria, Western Australia. Dependent Areas: Ashmore and Cartier Islands, Christmas Island, Cocos (Keeling) Islands, Coral Sea Islands, Heard Island and McDonald Islands, Norfolk Island.

Location of Australia

Differences between Australasia, Australian continent, the Commonwealth of Australia and Mainland Australia, clockwise from the top left

Australia is a continent located in the southern hemisphere between the Indian Ocean and the South Pacific Ocean. It is the largest country in Oceania, the largest country entirely in the Southern Hemisphere, and the largest country without land borders. Its geographic coordinates are 27 00 S, 133 00 E.

Australia is comprised of two land masses: mainland Australia and the island state of Tasmania to its far south. Australian territory and dependencies include thousands of islands that vary greatly in size and proximity.

Mainland Australia is bordered to the northeast by the Coral Sea, to the east by the Pacific Ocean, to the west by Indian Ocean, and to the southeast by the Tasman Sea, and the south by the frigid waters of the Southern Ocean that surround the Antarctic. Neighboring nations include Indonesia to the northwest, Papua New Guinea and the Solomon Islands to the northeast,

Australia' closest neighbor Papua New Guinea is only 74 kilometers (46 miles) away across the Arafura Sea. The islands Indonesia, which are across the Timor Sea, are almost as close. New Zealand is about 2,000 kilometers (1,200 miles) to the southwest across the Tasman Sea.

Geographical Data for Australia

Area: total: 7,741,220 square kilometers (2,989,577 square miles); land: 7,682,300 square kilometers (2,966,834 square miles), including Lord Howe Island and Macquarie Island; water: 58,920 square kilometers (22,749 square miles). Elevation: highest point: Mount Kosciuszko 2,228 meters (7,310 feet); lowest point: Lake Eyre -15 meters (-49 feet); mean elevation: 330 meters (1,083 feet). The highest point in Australian territory is Mawson Peak (2,745 meters, 9,006 feet high), located on Heard Island north of Antarctica. [Source: CIA World Factbook]

Coastline: 25,760 kilometers (16,007 miles); Maritime claims: territorial sea: 12 nautical miles (22.2 kilometers, 13.8 miles); contiguous zone: 24 nautical miles (44.4 kilometers, 27.6 miles); exclusive economic zone: 200 nautical miles (370.4 kilometers, 230.2 miles); continental shelf: 200 nautical miles (370.4 kilometers, 230.2 miles) or to the edge of the continental margin. Land Boundaries: none.

satellite composite image of Australia

Land Use: agricultural land: 46.65 percent (2018 estimate). Arable Land: 4.03 percent (2018 estimate); permanent crops: 0.04 percent (2018 estimate); permanent pasture: 42.58 percent (2018 estimate); forest: 17.42 percent (2018 estimate); other: 33.42 percent (2018 estimate). Arable land is land cultivated for crops like wheat, maize, and rice that are replanted after each harvest. Permanent crops is land cultivated for crops like fruit trees oranges that are not replanted after each harvest. Irrigated Land: 15,210 square kilometers (5,873 square miles) (2020). Most of the agricultural land is in Queensland and in Victoria. Most of the forests are in Queensland, Tasmania, Victoria and New South Wales.

Territorial Disputes Involving Australia: In 2004 Australia claimed a 1,000-nautical mile (1,852-kilometers, 1,151-mile) -wide maritime identification zone, an act that has caused concern among other states in the region. As of 2005, Australia and East Timor had failed to reach an agreement over how to delimit a permanent maritime boundary. In addition, the two nations disagree about how to share unexploited petroleum resources not covered by the 2002 Timor Sea Treaty. This bilateral dispute in turn has hampered revision of the maritime boundary between Australia and Indonesia; Indonesian groups dispute Australian claims over the Ashmore Reef. Australia also asserts land and maritime claims in Antarctica. [Source: Library of Congress, September 2005 **]

Topography of Australia

Australia is mostly low plateau with deserts, and a fertile plain in the southeast. Plateaus with areas of desert dominate the western two-thirds of Australia. The lowland plains of the east-central region gradually rise into a highland belt along the east coast. The wettest, greenest, and most populated areas are in the east and south. With the exception of the northeast, the country generally gets drier and flatter as one heads west and north.

Australia is commonly divided into four major topographic regions: 1) the eastern coastal plain, a generally low-lying and sandy strip that borders much of the continent’s eastern coastline; 2) the eastern highlands, a chain of mountains, plateaus, and uplands extending from Cape York Peninsula in northern Queensland through New South Wales and Victoria to Tasmania; 3) the central plains; and 4) the western plateau which occupies most of the western half of Australia. Rising generally between 300 and 600 meters (1,000 and 2,000 feet) above sea level, it is characterized by extensive deserts, sand-ridge systems, rocky plains, and sparsely vegetated landscapes.[Source: “Worldmark Encyclopedia of Nations”, 2007]

Relief map of Australia

Elevations in the eastern highlands range from about 300 meters (1,000 feet) to more than 2,100 meters (7,000 feet) above sea level. This area includes tablelands, plateaus and mountains such as the famous Atherton Tableland of Queensland, the Blue Mountains of New South Wales and the Grampians of Victoria. The central plains consist largely of a series of drainage basins running north to south across the continent. This area includes the Great Artesian Basin, one of the world's largest underground freshwater reservoirs, which underlies approximately 1,751,480 square kilometers (676,250 square miles) and forms the largest area of internal drainage on Earth.

Ilsa Sharp wrote in “CultureShock! Australia”: There are some very strange and dramatic excrescences on the otherwise flat Australian vistas, the most famous of these being the 335-meter (1,099-foot) tall Ayers Rock monolith, rising straight out of a central plain. The vivid red Olgas, rock monoliths described by an early explorer as ‘monstrous pink haystacks’, are in the Northern Territory, in the same Uluru National Park as Ayers Rock. Others include the Pinnacles, about 200 kilometers (124 miles) north of Perth in Western Australia — platoons of natural limestone obelisks standing up to two meters high (almost 7 feet) — and the ancient sandstone formations of the Bungle Bungle range in the remote Kimberley region of north-west Western Australia, rising 450 meters (1,476 feet) above the grasslands. [Source: Ilsa Sharp, “CultureShock! A Survival Guide to Customs and Etiquette: Australia”, Marshall Cavendish, 2009]

Australia — the World's Flattest Continent

Australia is the world's flattest continent. The only mountain range of any significance is Great Dividing Range which runs from north to south about a 161 kilometers (100 miles) inland from the east coast. These mountains may be "Great" on Australian terms, but are quite small when you compare them to the great ranges of other continents. The highest mountain, Mt. Kosciusko, is only Mount Kosciuszko 2,228 meters (7,310 feet) high.

Over millions of years, erosion has worn down its mountain ranges, leaving only about 6 percent of the continent above 600 meters (2,000 feet) in elevation. The average elevation of the continent is less than 300 meters (1,000 feet) above sea level. [Source: “Worldmark Encyclopedia of Nations”, 2007]

The Nullarbor Plains in the west are particularly flat. It is said that these plains are so flat that you can see the curve of the earth. It is certainly possible. One straight stretch of the of the Trans Australian railroad in the Nullarbor Plain is 500 kilometers (310 miles) long — the longest section of straight railroad in the world.

Grant McTainsh of Griffon University said that droughts and dust storms are causing Australia to become even flatter as millions of tons of top soil is blown into the oceans. One storm in October 2002, blew away 5 million tons of top soil in less than 24 hours.

Great Distances Between Places in Australia

Distances can be very great between places in Australia where the horizon often stretches endlessly in all directions. Open ‘empty’ land is an enduring image of Australia and ‘the tyranny of distance’ shapes life down under. ‘A wide brown land’ is what Aussie poet Dorothea Mackellar called Australia in her poem ‘My Country’.

Ilsa Sharp wrote in “CultureShock! Australia: If you are in Perth, Western Australia, you don’t just ‘run over’ to Sydney, or vice versa; it’s just like going ‘overseas’. You might as well ‘run over’ to Asia — it’s closer. So Australians are nonchalant about driving a few hours to visit the ‘rellies’ (relatives) for ‘tea’ (read ‘dinner’) or for a routine business meeting ‘just up the road’. [Source:Ilsa Sharp, “CultureShock! A Survival Guide to Customs and Etiquette: Australia”, Marshall Cavendish, 2009]

If they tell you the destination is ‘a cut lunch and waterbag’ away, better beware, because that will be quite a distance. And they are very car-bound. This is a land of big highways, articulated longdistance truck juggernauts and routine speeds of 110 kilometers per hour (70 miles per hour), Americans will recognise it.

Why is Australia the World’s Smallest Continent Not the Largest Island?

The distinction between an island and a continent is based largely on historical convention and geographic classification rather than a universally accepted scientific rule. Although both islands and continents are landmasses surrounded wholly or partly by water, there is no specific size threshold that separates one category from the other. As a result, the boundary between the two concepts is somewhat arbitrary and has been shaped by centuries of geographic tradition. [Source: Encyclopedia Britannica]

Australia occupies a unique position within this classification system. Covering approximately 7.7 million square kilometers (3.0 million square miles), it is recognized as the smallest continent on Earth. Because of its large size, geological history, and location on its own major tectonic plate, geographers classify Australia as a continent rather than an island. For this reason, Australia is often referred to as the “Island Continent.”

From a strictly literal perspective, Australia could be considered an island because it is completely surrounded by water. However, modern geographic authorities generally treat continents and islands as separate categories. Under this convention, a landmass classified as a continent is not simultaneously classified as an island, regardless of whether it is surrounded by water.

This distinction affects global rankings of landmasses. Since Australia is classified as a continent, Greenland is recognized as the world's largest island. Greenland covers approximately 2.17 million square kilometers (836,000 square miles), making it the largest landmass that is not considered part of a continent. Australia, by contrast, remains the smallest continent and the only continent entirely surrounded by ocean waters.

Pangea, Gondwana and Australia

Australia contains some of the oldest known material of terrestrial origin on Earth. Zircon crystals discovered in the Jack Hills region of Western Australia have been dated to approximately 4.4 billion years ago, making them the oldest known fragments of Earth's crust. The continent's oldest geological foundations consist of three ancient cratons—the North Australian, South Australian, and West Australian cratons. These stable continental cores form much of central and western Australia, while the younger eastern portion of the continent was built from geological material added along the continental margin during the last 500 million years. [Source: Charles Q. Choi, Live Science, December 24, 2023]

Australia was once part of the southern supercontinent Gondwana, which also included present-day Africa, South America, Antarctica, India, and Madagascar. Gondwana itself formed part of the larger supercontinent Pangaea, which began breaking apart about 200 million years ago. As Pangaea fragmented, Gondwana emerged as a separate continental mass before undergoing its own breakup.

Australia was home to a variety of dinosaurs, including ones that date before Australia separated from the Gondwana supercontinent 100 million years ago during the Cretaceous period and some when it was connected to Antarctica after that. Australia did not fully separate from Antarctica until approximately 35 million years ago, in the Eocene epoch.

Emergence of Australia 135 Million Years Ago

According to geologist Alan Collins of the University of Adelaide, Gondwana began splitting apart about 180 million years ago. Its eastern section, consisting of Australia, Antarctica, India, and Madagascar, separated from the western section, which included Africa and South America. Collins explained that this breakup was driven by subduction, a process in which oceanic crust sank beneath the southern and eastern margins of Asia. As the oceanic crust descended into the mantle, it pulled the attached tectonic plate with it, contributing to the fragmentation of Gondwana.

The eastern portion of Gondwana continued to break apart over time. As geologist Patrice Rey of the University of Sydney told Live Science, "Together as a single block, Australia and Antarctica separated from Gondwana about 135 million ago." Rey explained that this separation occurred because a tectonic plate located east of the Australia-Antarctica block was being forced beneath it. According to Rey, "This subduction zone accommodated the eastward motion of the Australia-Antarctica block away from Gondwana."

Australia and Antarctica remained connected for tens of millions of years after their separation from the rest of Gondwana. Over time, however, the two continents drifted apart as seafloor spreading created new oceanic crust between them. Australia gradually moved northward toward its present position.

New Zealand was also once connected to the Australia-Antarctica landmass. About 100 million years ago, the landmass that would become Zealandia—the mostly submerged continent that includes New Zealand—began separating from eastern Australia. This breakup was associated in part with major volcanic activity and tectonic stretching. As Zealandia subsided beneath the ocean, Australia continued its northward movement, eventually becoming the isolated continent recognized today.

Rivers in Australia

Major Rivers Murray River: 2,508 kilometers (1,558 miles); Darling River, a tributary of the Murray River: 1,545 kilometers (960 miles); Murrumbidgee River: 1,485 kilometers (923 miles); Lachlan River: 1,339 kilometers (832 miles); Cooper Creek: 1,113 kilometers (692 miles); Flinders River: 1,004 kilometers (624 miles). Several other rivers are important, but they generally carry lots of water in the wet season and are dry for the rest of the year. [Source: CIA World Factbook]

Australia main rivers

Major Watersheds Indian Ocean drainage: (Great Australian Bight): Murray-Darling (1,050,116 square kilometers, 405,451 square miles); Internal (endorheic basin) drainage: Lake Eyre (1,212,198 square kilometers, 468,032 square miles); Major Aquifers: Great Artesian Basin, Canning Basin.

Many of Australia’s rivers have highly variable flows. The most important river system, and the only one with a permanent, year-round flow, is that of the Murray, Darling, and Murrumbidgee rivers in the southeast, which covers more than 1 million square kilometers (miles), or around 14 percent of Australia. [Source: Library of Congress, September 2005 **]

Murray River begins in the Snowy Mountains and the Australian Alps of New South Wales in eastern Australia and flows some 2,600 kilometers (1,600 miles) west and southwest to empty into the sea below Adelaide, South Australia. Forming the boundary between New South Wales and Victoria it takes it time getting to the ocean, averaging only five kilometers (three miles) an hour. The Murray River is 2,508 kilometers (1,558 miles). As the crow flies the Murray covers a distance of about 9,500 kilometers (600 miles) but because it has so many twists and turns the actual length of the river is almost three times that distance.

The Murray River and Darling River are Australia's two longest rivers. Together with tributaries such as the Snowy, Lachlan, and Murrumbridge rivers the form a large catchment basin that encompasses four states and Canberra. The Murray-Darling River basin covers about 14 percent of Australia and drains an area the size of Spain and France combined. Australia’s breadbasket, it directly affect the lives about a sixth of Australia’s population and supplies 41 percent of Australia’s agricultural products as well as drinking water for millions.

Lakes in Australia

Major Lakes fresh water lake: Lake Alexandrina: 570 square kilometers (220 square miles); salt water lakes): Lake Eyre: 9,690 square kilometers (3,741 square miles); Lake Torrens (ephemeral): 5,780 square kilometers (2,232 square miles); Lake Gairdner: 4,470 square kilometers (1,726 square miles); Lake Mackay (ephemeral): 3,494 square kilometers (1,349 square miles); Lake Frome: 2,410 square kilometers (931 square miles); Lake Amadeus (ephemeral): 1,032 square kilometers (398 square miles). An ephemeral lake is a short-lived, temporary body of water that forms in an arid or semi-arid basin after heavy rainfall. These basins remain dry for extended periods—sometimes for years or even decades—until episodic flooding fills them, only for the water to eventually vanish as a result of strong evaporation

Satellital image of Lake Eyre filling up with water from its endorheic basin

Lake Eyre is the largest lake in Australia and one of the largest lakes in the world. The only problem is that it hardly ever has water in it. Most of the time it is a desolate expanse of cracked mud encrusted with a layer of salt. Since its discovery in 1840 it has only been completely filled twice: once in 1950 when a couple of men were actually shipwrecked on it and again in 1974.

Lake Eyre is located in Central Australia, spread across parts of the states of South Australia, Northern Territory and Queensland. The Lake Eyre basin is the lowest area of Australia: -15 meters (-49 feet) below sea level.

Measuring 9,690 square kilometers (3,741 square miles) it is one third the size of lake Ontario. It drains an area twice the size of Texas. Located in a part of the outback where the average rainfall of 13 centimeters (five inches) and the evaporation rate is very high so most of the water that falls in the lake's drainage basin during a cloudburst rarely makes it to the lake.

Coasts and Estuaries of Australia

Australia has a coastline of approximately 25,760 kilometers (16,007 miles) according to one source and 34,000 kilometers (21,130 miles) according to another, excluding its numerous offshore islands. Compared with many other continents, much of the coastline is relatively smooth, with relatively few large bays, deep inlets, or prominent capes. The two largest marine indentations are the Gulf of Carpentaria in the north, located between Arnhem Land and Cape York Peninsula, and the Great Australian Bight, a broad open bay along the continent’s southern coast. [Source: Geoscience Australia, Australian government; “Worldmark Encyclopedia of Nations”, 2007]

One of Australia's most significant coastal features is the Great Barrier Reef, which stretches for about 2,000 kilometers (1,243 miles) off the coast of Queensland. As the world's largest coral reef system, it consists of thousands of reefs and islands and supports an extraordinary diversity of marine life. The reef also plays an important role in tourism, fisheries, and coastal protection.

Australia's coastline contains more than 1,000 estuaries, where rivers meet the sea and freshwater mixes with saltwater. These estuarine environments support extensive wetlands, mangrove forests, salt marshes, mudflats, and seagrass beds. Coastal wetlands provide critical habitat for fish, birds, reptiles, and other wildlife, including many migratory species. They also help filter water, reduce coastal erosion, and buffer inland areas from storms and flooding.

Coastal and wetland environments form a dynamic transition zone between land and sea. Natural processes such as tides, waves, currents, river flows, and sediment movement continually reshape these landscapes. These environments provide important economic, social, and environmental benefits, supporting commercial fisheries, shipping, recreation, tourism, and biodiversity conservation.

Australia's population is heavily concentrated along the coast, with approximately half of all Australians living within 7 kilometers (4.3 miles) of the shoreline. Major cities, ports, industrial facilities, and tourism centers are located in coastal areas, making the management of coastal resources a significant national concern. Responsibility for most coastal management rests with the governments of the states and the Northern Territory, while the Australian Government oversees matters such as maritime boundaries, marine conservation, and navigation safety.

Australia's coastal wetlands range from tropical mangrove systems in the north to temperate estuaries and salt marshes in the south. Together with the continent's beaches, dunes, reefs, and estuaries, these wetlands form some of the country's most productive and ecologically important environments, supporting both human communities and a wide variety of native plant and animal species.

Image Sources: Wikimedia Commons

Text Sources: CIA World Factbook; “Encyclopedia of World Cultures, Volume 2: Oceania,” edited by Terence E. Hays, 1991, Wikipedia, New York Times, Washington Post, Los Angeles Times, Times of London, Lonely Planet Guides, Library of Congress, The Guardian, National Geographic, Smithsonian magazine, Encyclopedia.com, Live Science, The Conversation, The New Yorker, Reuters, Associated Press, Google AI, AFP, BBC, CNN, and various books, websites and other publications.

Last updated June 2026