The Sandover River is a river in northeast Central Australia. It is the only major tributary of the Georgina River that does not rise in western Queensland. Instead it flows from the eastern Macdonnell Ranges in the Northern Territory northward to enter the Georgina near Urandangi. The highest point in the catchment is Bald Hill at 996 metres (3,268 feet), but it enters the Georgina at altitudes below 200 metres (656 feet).
The Sandover is an ephemeral river, so it is usually dry except when the northern monsoon moves unusually far south into the continent. The average annual rainfall in the basin is typically around 275 mm (11 inches) but varies greatly: in dry years like 1928 the total may be as low as 50 mm (2 inches), but in very wet years like 1974, 2000, 2001 and 2010, it can be as high as 760 mm (30 inches). Most of this rain falls in the summer: between December and March monthly totals have on several occasions exceeded the mean annual rainfall. Flows in the Sandover often fail to reach the Georgina, instead drying out in waterholes well west of Urandangie. However in very wet periods, such as 1920-1921, 1973-1977 and 1999-2001, water from the Sandover may not only reach the Georgina, but actually flow (via a circuitous route) into Lake Eyre in South Australia.