The Registan Desert, also known as Sistan Desert, is an extremely arid plateau region located between Helmand and Kandahar provinces in the south-eastern Afghanistan. It is a sandy desert consisting of small, red sand hills about 50–100 feet (15–30 m) high, sand-covered plains, and open rocky and clay-covered areas. The underlying base of the hills consists of partly stabilized ancient transverse dunes, reflecting a west-to-east wind and nearly unlimited sand supply. The desert is very sparsely populated by Baluch and Pashtun nomads. The desert is gradually encroaching on surrounding agricultural areas.