Basin location

A basin, which can also be called a catchment, is an area of land where water collects and then drains into a large body of water such as a river, sea or ocean.
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In the Murray–Darling Basin, the water drains into the Murray and Darling rivers, and then into the Southern Ocean.

Start and end of the Basin

Most of the rivers in the Murray–Darling Basin start in the Great Dividing Range. The Basin ends in South Australia where the Murray Mouth meets the Southern Ocean.

The Basin is divided into 2 parts. Water in the northern Basin runs into the Darling River and water in the southern Basin runs into the River Murray.

To the south and east of the Basin are the mountains of the Great Dividing Range. This is a series of mountains on Australia’s east coast, which stretches from the north of Queensland, through New South Wales and into Victoria.

Most of the rivers that flow into the Basin start as fast-flowing streams in these mountains. However, most of the Basin lies on flat plains which are not far above sea level. The rivers in these areas tend to flow more slowly.

For a detailed description of the geography of each river catchment, see the Basin catchment profiles.

The rivers in the Basin form Australia’s largest river system. Find out more about the rivers, floodplains and wetlands in the Basin.

The Basin at a glance

  • The Murray–Darling Basin covers an area in the south east of Australia.
  • It covers more than 1 million square kilometres. 
  • It is about the size of France and Spain joined together, or a little bigger than Egypt.
  • The Basin covers 75% of New South Wales, more than 50% of Victoria, 15% of Queensland, 8% of South Australia and all of the Australian Capital Territory.
  • The length of the Basin is almost 1,400 km from the source of the Warrego River in Queensland to the headwaters of the Goulburn River in Victoria.
  • The width of the Basin is as much as 1,200 km along the Murray valley in the southern Basin. However most of the Basin measures 800 km to 900 km wide from the Great Dividing Range in the east to the plains beyond the Darling (Baaka) River in western Queensland and New South Wales.
  • It is an area of significant cultural importance to First Nations people.
  • It is Australia’s most important water catchment, providing water to 2.4 million people, countless native habitats and thousands of farms.

Last updated: 11 December 2023