is the capital city of South Australia and the fifth-largest city in Australia. In June 2013, Adelaide had an estimated resident population of 1.29 million. The demonym "Adelaidean" is used in reference to the city and its residents. Adelaide is north of the Fleurieu Peninsula, on the Adelaide Plains between the Gulf St Vincent and the low-lying Mount Lofty Ranges which surround the city. Adelaide stretches 20 km (12 mi) from the coast to the foothills, and 90 km (56 mi) from Gawler at its northern extent to Sellicks Beach in the south..