In addition to being the smallest continent, Australia is the flattest and the second-driest, after Antarctica. The continent is sometimes called Oceania, to include the thousands of tiny islands of the Central Pacific and South Pacific, most notably Melanesia, Micronesia, and Polynesia (including the U.S. state of Hawai'i). However, the continent of Australia itself includes only the nation of Australia, the eastern portion of the island of New Guinea (the nation of Papua New Guinea) and the island nation of New Zealand. Australia covers just less than 8.5 million square kilometers (about 3.5 million square miles). Its population is about 31 million. It is the most sparsely populated continent, after Antarctica.
A plateau in the middle of mainland Australia makes up most of the continent’s total area. Rainfall is light on the plateau, and not many people have settled there. The Great Dividing Range, a long mountain range, rises near the east coast and extends from the northern part of the territory of Queensland through the territories of New South Wales and Victoria. Mainland Australia is known for the Outback, a desert area in the interior. This area is so dry, hot, and barren that few people live there. In addition to the hot plateaus and deserts in mainland Australia, the continent also features lush equatorial rainforests on the island of New Guinea, tropical beaches, and high mountain peaks and glaciers in New Zealand.