Chott Melrhir (Arabic: شط ملغيغ‎) also known as Chott Melghir or Chott Melhir is an endorheic salt lake in northeastern Algeria. It is the westernmost part of a series of depressions, which extend from the Gulf of Gabès into the Sahara. They were created between Miocene and Early Pleistocene as a result of compression accompanying the formation of the Atlas Mountains. With the maximum area of about 6,700 km2 (2,600 sq mi), Chott Melrhir is the largest lake in Algeria. It lies almost entirely below the sea level and contains the lowest point in Algeria, −40 meters (−130 feet). Its size varies over the year and is usually larger than 130 km (81 mi) from east to west. The nearby cities are Biskra (60 km north-west), El Oued and Touggourt (85 km south).