Perth is situated in Western Australia and is the largest city and capital of the state. Perth has a population of 1.8 million people living in its metropolitan area, which covers 5,386 square kilometers (2,079 square miles). The fifth largest city in Australia is Adelaide, the South Australian capital.he capital of Australia is Canberra, which is located in the Australian Capital Territory in southeastern Australia. Canberra has a population of about 367,000, making it the largest inland city in the country, but the eight largest city in all.