The Darling is Australia’s longest river with its headwaters being known as the Severn River in the Great Divide.  It is then progressively named the Dumaresq, the Macintyre, the Barwon and finally the Darling just upriver from Bourke.  Between the Severn River and Tenterfield Creek junction and the town of Mungindi, the river forms the border between New South Wales and Queensland – about 460 kilometres.

The principal tributaries are the Condamine River and the Balonne River in Queensland, the Gwydir, Namoi, Castlereagh, Macquarie and Bogan Rivers in New South Wales and the intermittent tributaries Paroo and Warrego Rivers from the arid interior.  As it approaches Wilcannia, the river, instead of receiving tributaries, forms distributaries.

Near Menindee is a series of broad shallow basins stretching for fifty kilometres along the western bank of the river.  These are the Menindee Lakes that are part of a major water conservation scheme.  Below Menindee, the Great Anabranch leaves the Darling on the right to follow a separate course for 480 kilometres before joining the Murray River thirty kilometres downstream from Wentworth.

The Darling River has a very low gradient (approximately 46 mm to one kilometre) and in places winds three kilometres to cover one.  The water level can change dramatically, although the seven weirs between Mungindi and Wentworth serve to control this.  The great variation in water level is best illustrated by the Bourke wharf.  It was twelve metres high with three loading stages one above the other, used as the water rose or fell.

In 1828 Charles Sturt set out to explore the Macquarie River and on 2 January 1829 he discovered the Darling River, naming it after Sir Ralph Darling, Governor of New South Wales.  In 1830 Sturt followed the Murrumbidgee into the Murray River.  During this journey he saw “a new and beautiful stream” coming apparently from the north. After a short journey up this river he correctly identified it as the Darling River, whose upper reaches he had discovered the year before.

By the 1890s most of the land was occupied by pastoralists.  The stocking rate is extremely low but some of the finest merino wool in the world is produced there.  The use of the river for transport commenced in the 1850s and river trade by barge and side paddle steamers prospered until early in the 20th century.