Emi Koussi is a high 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 3415 m in altitude, rising 2.3 km above the surrounding sandstone plains. The volcano is 60 by 80 km wide.
Two nested calderas cap the volcano, the outer one being about 12 by 15 km in size. Within it on the southeast side is a smaller caldera, about 2-3 km wide and 350 m deep. Numerous lava domes, cinder cones, maars, and lava flows are found both within the calderas and along the outer flanks of the shield.
Elevation: 3,445 metres (11,302 feet)
Type: Shield volcano
Age of rock: Holocene
Last eruption: unknown