Central Australia, also sometimes referred to as the Red Centre, is an inexactly defined region associated with the geographic centre of Australia. In its narrowest sense it describes a region that is limited to the town of Alice Springs and its immediate surrounds including the MacDonnell Ranges. Commonly, it refers to an area up to 600 km (370 mi) from Alice Springs, in every direction. In its broadest use it can include almost any region in inland Australia that has remained relatively undeveloped, and in this sense is synonymous with the term Outback.

Mainland Australia is the main landmass of the Australian continent, excluding the Aru Islands, New Guinea, Tasmania, and other Australian offshore islands. The landmass also constitutes the mainland of the territory governed by the Commonwealth of Australia, and the term, along with continental Australia, can be used in a geographic sense to exclude surrounding continental islands and external territories. Generally, the term is applied to the states of New South Wales, Queensland, South Australia, Victoria, and Western Australia, as well as the Australian Capital Territory, Jervis Bay Territory, and Northern Territory.