Indigenous Australians are descendants of the first known human inhabitants of the Australian continent and its nearby islands. The term includes both the Torres Strait Islanders and the Aboriginal People, who together make up about 2.5% of Australia's population. The latter term is usually used to refer to those who live in mainland Australia, Tasmania, and some of the other adjacent islands. The Torres Strait Islanders are indigenous Australians who live in the Torres Strait Islands between Australia and New Guinea. Indigenous Australians are recognised to have arrived between 40,000 and 70,000 years ago, though the lower end of this range has wider acceptance.
The term Indigenous Australians encompasses many diverse communities and societies, and these are further divided into local communities with unique cultures. Fewer than 200 of the languages of these groups remain in use — all but 20 are highly endangered. It is estimated that prior to the arrival of British settlers the population of Indigenous Australians was up to 1 million. The distribution of people was similar to that of the current Australian population, with the majority living in the south east centered along the Murray River.