Mandurah () is a coastal city in the Australian state of Western Australia, situated approximately south of the state capital, Perth. It is the state's second most populous city, with a population of 107,641 as of the 2021 census. Mandurah's central business district is located on the Mandurah Estuary, which is an outlet for the Peel Inlet and Harvey Estuary. The city's name is derived from the Noongar word mandjar, meaning "meeting place" or "trading place". A townsite for Mandurah was laid out in 1831, two years after the establishment of the Swan River Colony, but attracted few residents, and until the post-war boom of the 1950s and 1960s it was little more than a small fishing village. In subsequent years, Mandurah's reputation for boating and fishing attracted many retirees, including to the canal developments in the city's south. Along with four other local government areas (Boddington, Murray, Serpentine-Jarrahdale, and Waroona), the City of Mandurah is included in the wider Peel region. Mandurah is sometimes grouped together with Perth for statistical purposes, especially since the extension of the Kwinana Freeway and the completion of the Mandurah railway line in the late 2000s. The two cities now form a conurbation along the Indian Ocean coastline, although the Perth metropolitan area officially ends at Singleton around north of Mandurah's city centre. Geography Mandurah has grown from isolated holiday communities along the shores of the Peel-Harvey Estuary to a major regional city in just over a decade, in a similar vein to the Gold Coast in Eastern Australia. In recent times, it has formed a conurbation with Perth along the coast; it is only south of Rockingham, a southern suburb of Perth. Mandurah has also become a popular lifestyle alternative for Perth retirees and its connection with the Perth CBD has been strengthened with the opening of the Perth-Mandurah railway line in December 2007 and a direct road connection to the Kwinana Freeway built by late 2010. A housing affordability survey of 227 cities in 2008 ranked it the least affordable city in Australia. Geology The waters of the Peel Inlet and Harvey Estuary (one of Australia's larger inlet systems) form the centre of Mandurah. The estuary is approximately twice the size of Sydney Harbour. The city lies in and around this freshwater system which in turn feeds into the Indian Ocean. The city and its suburbs have many kilometres of ocean coastline