Fed by melting snow at its source in the Mount Kosciusko region, and by large tributaries like the Darling and Murrumbidgee rivers, the Murray gains enough volume to cross the dry plains which bear its name. It meets the sea on the south coast, east of Adelaide. The Murray-Darling-Murrumbidgee network is the most important river system in Australia. It drains more than 1.1 million sq km (415,000 sq mi) in Queensland, New South Wales, Victoria, and South Australia, and waters some of the country’s most important arable and grazing lands. Much of the network is also navigable during the wet season. The Murray forms most of the border between New South Wales and Victoria.

The other rivers of central Australia, like those of the western part of the continent, flood adjacent, low-lying land when it rains. At other times they are dry channels, or at best a series of water holes; the central plains region is sometimes known as the Channel Country. The Victoria, the Daly, and the Roper rivers drain a section of the Northern Territory. In Queensland the main rivers flowing north to the Gulf of Carpentaria are the Mitchell, the Flinders, the Gilbert, and the Leichhardt.

Western Australia has few significant rivers. The most important are the Fitzroy, the Ashburton, the Gascoyne, the Murchison, and the Swan rivers.

The natural lakes of the interior of continental Australia are salinas, or salt lakes. Fed by ephemeral or intermittent streams and rivers, they receive water rarely and are normally reduced by evaporation to salt-encrusted swamp beds or salt pans. The large salinas in the centre and south of the Great Artesian Basin—lakes Eyre, Torrens, Frome, and Gairdner—are the remains of a vast inland sea which once extended south from the Gulf of Carpentaria.