The Sous or Souss (Berber: Sus) is a region in southern Morocco. Geologically, it is the alluvial basin of the Oued Sous (Asif n Sus), separated from the Sahara by the Anti-Atlas Mountains. The natural vegetation in the Sous is savanna dominated by the Argan (Argania spinosa), a local endemic tree found nowhere else; part of the area is now a UNESCO Biosphere Reserve to protect this unique habitat.