Dhar Adrar

The Adrar
Natural region
Landscape of the stony desert known as Reg de l'Adrar
Location of the Adrar in central Mauritania
Country	Mauritania
Elevation	340 m (1,120 ft)

The Adrar (Berber: , lit. mountain) is a highland natural and historical region of the Sahara Desert in northern Mauritania. The Adrar Region, an administrative division of Mauritania, is named after the traditional region. It is sometimes called Adrar Tamar to distinguish it from other areas called Adrar in the Sahara.

The Adrar is an arid plateau, known for its gorges, regs (stony deserts) and sand dunes. Structurally the Adrar is a low central massif which rises to over 700 m (2,297 ft) above sea level just east of Atar near the Ebnou Pass on the track to Chinguetti, then loses elevation and becomes subsumed by dunes to the south and east. Limited cultivation is only possible in the gorges at lower elevations where the water table is high enough to support large palm groves.

Notable features include the Oued el Abiod or 'White Valley', a dune-filled fault line along which many small settlements and palm groves are found. The Guelb Aouelloul crater is 3.1 million-old impact crater which was studied by the noted Saharan scholar, Théodore Monod. To the east beyond Ouadane is the distinctive Richat Structure, an uplifted and then heavily eroded dome of strata approximately 40 km across and whose concentric rings resemble an impact crater when observed from space.