Australia (/ɒˈstreɪliə/, /ə-/, or colloquially /-jə/),[10][11] officially the Commonwealth of Australia,[12] is anOceanian country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area. Neighbouring countries include Indonesia, East Timor andPapua New Guinea to the north; the Solomon Islands and Vanuatu to the north-east; and New Zealand to the south-east.

For at least 40,000 years[13] before the first British settlement in the late 18th century,[14][15] Australia was inhabited byindigenous Australians,[16] who spoke languages grouped into roughly 250 language groups.[17][18]

After the European discovery of the continent by Dutch explorers in 1606, Australia's eastern half was claimed byGreat Britain in 1770 and initially settled through penal transportation to the colony of New South Wales from 26 January 1788. The population grew steadily in subsequent decades; the continent was explored and an additional five self-governing crown colonies were established.