High Quality Content by WIKIPEDIA articles! Emi Koussi is a high pyroclastic shield volcano that lies at the south end of the Tibesti Mountains in the central Sahara of northern Chad. It is the highest mountain in Chad, and the highest in the Sahara. The volcano is one of several in the Tibesti massif, and reaches 3445 m in altitude, rising 2.3 km above the surrounding sandstone plains. The volcano is 60 by 80 km wide.