Chott Melrhir (Arabic: شط ملغيغ) is a large endorheic salt lake in northeastern Algeria. Chott Melrhir has an area of about 6700 km² and is the largest lake in Algeria. It also lies almost entirely below the sea level, the lowest point of Algeria is located here. It regularly dries up thus becomes a salt pan. The cities of Biskra, El Oued and Touggourt lie nearby. Chott Melrhir is designated a Ramsar wetland of international importance.