Perth is a region of the vast state of Western Australia. It is centred around the states capital city, Perth, one of the most isolated capital cities in the world. The Perth inner area radiates north and south of the Swan River on a flat coastal plain, bounded in by the Darling Scarp to the east and the Indian Ocean coastline in the west. Perth has a population of around 1.6 million (2009), making it the fourth largest city in Australia. The many uncrowded beaches along the Perth coastline define the lifestyle: Perth is laid-back, quiet and safe.