Djanet, and the nearby towns of Azelouaz, El Mihan, Adjahil and Eferi, lie in a valley carved by the intermittent river (wadi) Oued Idjeriou through the southwest edge of the Tassili n'Ajjer mountain range and east of the Erg Admer sand dunes. The Tadrart Rouge is located to the southeast and is a southern prolongation of the Libyan Tadrart Acacus.