Perth is the capital and largest city of the Australian state of Western Australia, and the fourth-largest city in Australia, with a population of 1,554,769 (2007 estimate). One of its LGAs, the City of Perth, is currently the fastest growing area in Australia in percentage terms (10% per year). Perth was founded on 12 June 1829 by Captain James Stirling as the political centre of the free settler Swan River Colony. It has continued to serve as the seat of Government for Western Australia to the present day.

The metropolitan area is located in the south west of the continent between the Indian Ocean and a low coastal escarpment known as the Darling Range. The central business district and suburbs of Perth are situated on the Swan River.

Perth became known worldwide as the "City of Light," as city residents lit their houselights and streetlights as American astronaut John Glenn passed overhead while orbiting the earth on Friendship 7 in 1962. The city repeated its feat as Glenn passed overhead on the Space Shuttle in 1998.

Before European settlement, the area had been inhabited by the Whadjuk Noongar people for over 40,000 years, as evidenced by archaeological findings on the Upper Swan River. These Aborigines occupied the southwest corner of Western Australia, living as hunter-gatherers. The lakes on the coastal plain were particularly important to them, providing both spiritual and physical sustenance.

The area where Perth now stands was called Boorloo by the Aboriginals living there at the time of their first contact with Europeans in 1827. Boorloo formed part of Mooro, the tribal lands of the Yellagonga, one of several groups based around the Swan River and known collectively as the Whadjuk.

The first documented European sighting of the region was made by the Dutch Captain Willem de Vlamingh and his crew on 10 January 1697. Subsequent sightings between this date and 1829 were made by other Europeans, but as in the case of the sighting and observations made by Vlamingh, the area was considered to be inhospitable and unsuitable for the agriculture which would be needed to sustain a settlement.

After a referendum in 1900, Western Australia joined the Federation of Australia in 1901. It was the last of the Australian colonies to agree to join the Federation, and did so only after the other colonies had offered several concessions, including the construction of a transcontinental railway line to Perth (via Kalgoorlie) from the eastern states.

In 1933, Western Australia voted in a referendum to leave the Australian Federation, with a majority of two to one in favour of secession. However, an election held shortly before the referendum had turned out the incumbent "pro-independence" government, replacing it with a government which did not support the independence movement. Respecting the result of the referendum, the new government nonetheless petitioned the Agent General of the United Kingdom for independence, where the request was simply ignored.

Perth is one of the most isolated metropolitan areas on earth. The nearest city to Perth with a population over one million is Adelaide in South Australia, which is 2,104 kilometres (1,307 mi) away. Perth is geographically closer to Dili (East Timor), Singapore and Jakarta (Indonesia), than it is to Sydney, Melbourne, and Brisbane.