The Murzuq Desert, Idehan Murzuq, Idhan Murzuq, (also Murzaq, Murzuk, Marzuq and Murzak), is an erg in southwestern Libya with a surface of approximately 58,000 km2. It is named after the town of Murzuk in the Fezzan. Like the Idehan Ubari further north, the Idehan Murzuq is part of the greater Sahara Desert region. It is separated from the southern Sahara Desert by the Tibesti Mountains and the Tassili n'Ajjer.