South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. With a total land area of 984,310 square kilometres (380,044 sq mi), it is the fourth-largest of Australia's states and territories by area, which includes some of the most arid parts of the continent, and with 1.5 million people, it is the fifth-largest of the states and territories by population. This population is the second-most highly centralized in the nation after Western Australia, with more than 67% of South Australians living in the capital Adelaide or its environs. Other population centres in the state are relatively small; Mount Gambier, the second-largest centre, has a population of 26,878.
South Australia shares borders with all the other mainland states. It is bordered to the west by Western Australia, to the north by the Northern Territory, to the north-east by Queensland, to the east by New South Wales, and to the south-east by Victoria. To the south, its border is the ocean, the Great Australian Bight.