South Australia (abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the continent. With a total land area of 983,482 square kilometres (379,725 sq mi), it is the fourth largest of Australia's states and territories.
South Australia shares borders with all of the other mainland states, and with the Northern Territory; 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, to the south-east by Victoria, and to the south by the Great Australian Bight and the Indian Ocean. With over 1.6 million people, the state comprises less than 8% of the Australian population and ranks fifth in population among the states and territories. The majority of its people reside in the state capital, Adelaide, with most of the remainder settled in fertile areas along the south-eastern coast and River Murray. The state's origins are unique in Australia as a freely settled, planned British province, rather than as a convict settlement. Official settlement began on 28 December 1836, when the colony was proclaimed at The Old Gum Tree by Governor John Hindmarsh.