The Simpson Desert is a vast expanse of red sand plains and parallel dunes spanning the Northern Territory, South Australia and Queensland in central Australia. Known to the Wangkangurru Yarluyandi people as Munga-Thirri, it covers 176,500 square kilometres, making it Australia’s fourth-largest desert.
The desert is defined by the world’s longest parallel sand dunes, static north-south ridges held in place by vegetation that range from three metres high in the west to around 30 metres on the eastern side. The tallest, Nappanerica (Big Red), reaches 40 metres. Beneath the surface lies the Great Artesian Basin, one of the planet’s largest inland drainage systems, which feeds natural springs such as Dalhousie Springs and historic bores drilled for stock routes and petroleum exploration. This groundwater system is also part of the Lake Eyre basin, though bore extraction has steadily reduced spring flows in recent decades, raising concerns about the desert’s fragile water balance.
