Ryn-Peski or Ryn Desert are sandy desert massifs and dunes in the Caspian Lowland of Kazakhstan, located on the watershed of the Volga and Ural rivers. They occupy an area of about 40 thousand km².
The desert is partly covered with grass and bushes. Dry winds and dust storms are typical for the Ryn Sands. Fresh waters are relatively shallow. The sands begin at the village of Khan Ordasy in the West Kazakhstan region of Kazakhstan, which is heavily covered with them, and from there they go southeast in a strip from 21 to 43 km wide and up to 160 km long. This entire sea of sand or dunes is in places quite high hills, up to 13 m high, consisting of completely clean, reddish-yellow sand containing sea shells.