Perth is the capital city of Western Australia. It serves as a major urban center in the South West Land Division, with most of its metropolitan area situated on the Swan Coastal Plain between the Indian Ocean and the Darling Scarp.
As of 2023, Perth is the fourth-most-populous city in Australia, with a population exceeding 2.3 million within Greater Perth. The city has expanded outward from original British settlements located on the Swan River, which also hosts its central business district and the port of Fremantle.
By certain criteria, Perth is considered the world's most isolated major city. Its geographical layout is defined by its position along the coast and its historical development centered around the river system.