Officially the Commonwealth of Australia is a country in the southern hemisphere comprising the mainland, which is both the world's smallest continent and the world's largest island, the island of Tasmania, and numerous other islands in the Indian and Pacific Oceans.  It is the only area of land simultaneously considered a continent, a country and an island. Neighboring countries include Indonesia, East Timor and Papua New Guinea to the north, the Solomon Islands, Vanuatu and New Caledonia to the north-east and New Zealand to the southeast.

For around 40,000 years before European settlement commenced in the late 18th century, the Australian mainland and Tasmania were inhabited by around 250 individual nations of indigenous Australians.  After sporadic visits by fishermen from the immediate north, and European discovery by Dutch explorers in 1606, the eastern half of Australia was claimed by the British in 1770 and initially settled through penal transportation to the colony of New South Wales, founded on 26 January 1788. The population grew steadily in the following years; the continent was explored, and during the 19th century another five largely self-governing Crown Colonies were established.