The Simpson Desert is the Australian desert famous for its parallel red sand dunes, including Big Red near Birdsville.
It lies mainly in central Australia, across Queensland, the Northern Territory, and South Australia. Its dunes are shaped by prevailing winds and can extend for many kilometres in remarkably regular lines. Big Red, near Birdsville, is one of the best-known dunes and a popular landmark for four-wheel-drive travellers.
The Simpson is part of the vast arid interior often called the Australian Outback. Despite its harsh appearance, it supports spinifex grasses, reptiles, birds, and mammals adapted to scarce water. Rainfall is highly variable rather than completely absent, and temporary waterholes can appear after storms.
The desert is sometimes confused with the broader deserts around it, including the Sturt Stony Desert and the Tirari Desert. The Simpson is especially distinctive for its long, parallel dune system.