, a mountain massif of the central Sahara, forming part of the elevated land running from the Adrar of the Ifog̲h̲as [see adrar ] in northeastern Mali to the Nuba mountains of Sudan.

It lies roughly between lats. 23° and 19° 30′ N. and longs. 16° and 19° 30′ E., being about 480 km/300 miles long and up to 350 km/200 miles wide, and includes the highest peak of the Sahara, the volcanic summit Emi Koussi (3,415 m/11,200 feet). Three great, deeply-cut dry wadis indicate, as elsewhere in the Sahara, a formerly more humid climate. T…