South Australia is a state in the southern central part of Australia. With a total land area of 984,314 square kilometres (380,046 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. It is the 17th-largest subdivision in the world and the fifth-largest in Australasia. It is the second-most highly centralised state in the nation after Western Australia, with more than 67% of the 1.9 million South Australians living in the capital Adelaide or its environs. Other population centres in the state are relatively small; with Mount Gambier being the second-largest centre, with a population of 26,878.