Brisbane, Australia, was flooded when the Brisbane River broke its banks.

Brisbane is the capital and largest city of the state of Queensland and the third-most populous city in Australia, with a population of approximately 2.8 million. Brisbane lies at the centre of South East Queensland, an urban agglomeration with a population of over 4 million. The central business district is situated within a peninsula of the Brisbane River about 15 km (9 mi) from its mouth at Moreton Bay. Brisbane's metropolitan area sprawls over the hilly floodplain of the Brisbane River Valley between Moreton Bay and the Taylor and D'Aguilar mountain ranges, encompassing several local government areas, most centrally the City of Brisbane. The demonym of Brisbane is Brisbanite.

In January 1974 a flood occurred in Brisbane, Queensland, Australia after three weeks of continual rain. The Brisbane River, which runs through the heart of the city, broke its banks and flooded the surrounding areas. The cyclone that produced the flood also flooded surrounding cities: Ipswich, Beenleigh, and the Gold Coast.

The Brisbane River is the longest river in South East Queensland, Australia. It flows through the city of Brisbane, before emptying into Moreton Bay on the Coral Sea. John Oxley, the first European to explore the river, named it after the Governor of New South Wales, Sir Thomas Brisbane in 1823. The penal colony of Moreton Bay later adopted the same name, eventually becoming the present city of Brisbane. The river is a tidal estuary and the water is brackish from its mouth through the majority of the Brisbane metropolitan area westward to the Mount Crosby Weir. The river is wide and navigable throughout the Brisbane metropolitan area. It is affectionately known by locals as the "Brown Snake", on account of its silty waters and long, winding course.