Adelaide is the capital city of the state of South Australia, and the fifth-most populous city of Australia. The demonym Adelaidean is used to denote the city and its residents.
Adelaide is situated on the Adelaide Plains north of the Fleurieu Peninsula, between the Gulf St Vincent in the west and the Mount Lofty Ranges in the east. Its metropolitan area extends 20 km (12 mi) from the coast to the foothills, and stretches 96 km (60 mi) from Gawler in the north to Sellicks Beach in the south.
Named in honour of Queen Adelaide, consort to King William IV, the city was founded in 1836 as the planned capital for the only freely-settled British province in Australia. Colonel William Light, one of Adelaide's founding fathers, designed the city centre and chose its location close to the River Torrens, in the area originally inhabited by the Kaurna people and known as Tarndanyangga ("place of the red kangaroo"). Light's design, now listed as national heritage, set out the city centre in a grid layout, interspaced by wide boulevards and large public squares, and entirely surrounded by parklands.