Some Facts about Australia and Oceania
Australia, Map of Australia:: Australia is the smallest of the seven continents on Earth. The first people to discover and settle Australia about 50,000 years ago were the ancestors of the Aboriginal Australians.
The discovery by the Europeans was a long time coming. It was not until 1606 that Dutch and Spanish explorers landed on the continent. In 1770 James Cook, a colorful figure in British colonial history, was in search for the predicted Great South Land. He came across a vast stretch of unknown land when he arrived on the east coast of Australia, and in the usual blunt British fashion, he claimed the territory for the British Crown.
Between 1788 and 1868 the British used Australia as a penal colony. Australia became independent from the UK in several stages, only on the 3rd March 1986, Australia achieved complete independence from Britain.
Area of Australia:: Including the adjacent island of Tasmania, Australia covers an area of 7,692,024 km² (2,969,907 sq mi), which corresponds to about 5.6% of Earth's landmass. In comparison, Australia is slightly smaller than the contiguous United States. One country, Australia, occupies the continent.
Oceania:: There is a variety of definition of Oceania. The most plausible is to denote the insular area in the Pacific Ocean east of Maritime Southeast Asia and Australia and west of South America (see the map below).
How many countries are there in Oceania? There are 14 independent countries and a number of dependent territories as detailed under.
Area:: Oceania covers an area of about 100 million square kilometers, this is about one-fifth of Earth's surface area. By far the largest country by area is Australia with 7,692,024 km², followed by Papua New Guinea with 462,840 km². The smallest independent country in Oceania is the island nation of Nauru with 21 km².
Australia/New Zealand sometimes referred to as Australasia.
Australia is known as the smallest continent on Earth. The country has an area of 7,692,000 km² (2,969,900 sq mi), making it slightly smaller than the contiguous United States. According to its population clock, 25,479,630 people live in Australia. (2019). 
New Zealand is a geographically isolated island nation in the southern Pacific, situated about 2,000 km (1,250 mi) southeast of Australia's east coast. 4.7 million people live in New Zealand (in 2019) . The country consists of two main islands, known as the North Island (Te Ika-a-Māui), and the South Island (Te Waipounamu).
Melanesia is a region in the western Pacific Ocean to the east and south of New Guinea Island; its northern boundary is the Equator. The area includes the island of New Guinea, the Bismarck Archipelago, four independent countries: Vanuatu, the Solomon Islands, Fiji, and Papua New Guinea, and the French dependency of New Caledonia. Many islands of Melanesia are of volcanic origin and belong to the Pacific Ring of Fire.
Micronesia is a region in the western Pacific Ocean, north of Melanesia and north and west of Polynesia; its southern boundary is largely along the Equator. The area includes the Mariana Islands, the Federated States of Micronesia, the Republic of Palau, the Marshall Islands, and the western portion of the Kiribati archipelago. In 2019 an estimated 537,000 people live in Micronesia.
The term Polynesia refers to a vast region of the central Pacific Ocean to the east of Micronesia and Melanesia. The ocean section contains the easternmost of the Pacific islands, including New Zealand, the Cook Islands, Hawaii, the Marquesas Islands, Samoa, and French Polynesia. In 2019 an estimated 2 million people live in Polynesia (including Hawaii but not New Zealand).
More about Oceania
Oceania's major Regions and Subregions
The island world of Oceania is divided into:
Australia, a country and Earth's smallest continent.
Zealandia, a microcontinent which includes the island country of New Zealand.
New Guinea, the second largest island on the planet (after Greenland),
The Pacific Islands, thousands of islands in the Pacific Ocean divided into Melanesia, Micronesia, and Polynesia.
An estimated 42.6 million people live in Oceania/Australia; about 0.54 % of the world's population (7.8 billion).
The most populous countries in Oceania are Australia with 25.6 million people, Papua New Guinea with 9 million, and New Zealand with 5 million residents (in 2020).
(Source: UN World Population Prospects)
Largest Metropolitan Areas
Largest cities in Oceania by population are
Sydney, Melbourne, Brisbane, Perth, and Auckland; except Auckland, all cities are located in Australia.
Major Physiographic Features of Oceania
Major physiographic regions of Australia/Oceania includes:
The southwestern part of the Pacific Ring of Fire, the Great Barrier Reef, Australia's Outback, the Great Dividing Range in Australia, the North Island Volcanic Plateau and the Southern Alps in New Zealand, the rain forest covered New Guinea Highlands and the coral islands of Micronesia and Polynesia.
Puncak Jaya or Carstensz Pyramid in the Papua Province of Indonesia on the island of New Guinea is at 4,884 m (16,024 ft) the highest mountain in Oceania.
Mauna Kea at 4,207.3 m (13,803 ft) above sea level on the island of Hawaii is Oceania's second-highest peak.
Mount Kosciuszko at 2,228 m (7,310 ft) in New South Wales is the highest mountain in Australia.
The Great Dividing Range, also known as the Eastern Highlands is a 3,500 km long mountain range along the eastern coast of Australia. The highest peak is Mount Kosciuszko at 2,228 m (7,310 ft). Puncak Jaya (4,884 m) is the highest mountain in the Makoe Mountains, a section of the New Guinea Highlands, the mountain chain stretches almost the entire island.
The largest lake in Oceania/Australia is theoretically Lake Eyre in South Australia, a seasonal lake with a surface area between 8,000 and 9500 km².
The longest single river in Oceania is the Murray at 2508 km.  For a long distance, the river forms the border between the Australian states of Victoria and New South Wales.
About 35% of the Australian continent is dry, most of the interior, known as "The Outback", receives so little rain that it is practically a desert. There are several named deserts in Australia. The largest by area is the Great Victoria Desert, followed by the Great Sandy Desert, the Tanami Desert, the Simpson and the Gibson deserts, and the Strzelecki Desert.
Languages of Oceania:
Many different languages were spoken in Oceania before the arrival of the Europeans. The major languages spoken today in Oceania are based on English, some French-based creole, some Japanese, Aboriginal and Torres Strait Islander languages, Melanesian Pidgin, Hawaiian, Polynesian languages, Tahitian, and Maori.