Lake Assal is a crater lake in central-western Djibouti. It is located at the western end of Gulf of Tadjoura between Arta Region, and Tadjoura Region, touching Dikhil Region, at the top of the Great Rift Valley, some 120 km (75 mi) west of Djibouti city.

Lake Assal is a saline lake that lies 155 m (509 ft) below sea level in the Afar Triangle, making it the lowest point on land in Africa and the third-lowest point on Earth after the Sea of Galilee and the Dead Sea. No outflow occurs from the lake, and due to high evaporation, the salinity level of its waters is 10 times that of the sea, making it the third most saline body of water in the world behind Don Juan Pond and Gaet'ale Pond.

Lake Assal is the world's largest salt reserve, which is exploited under four concessions awarded in 2002 at the southeast end of the lake; the major share of production (nearly 80%) is held by Société d’Exploitation du Lac and Société d’Exploitation du Salt Investment S.A de Djibouti.

Lake Assal, in an oval shape (length 19 km and width 6.5 km), consists of two distinct parts; one is "crystallised salt surface" zone of 68 km2 and the other is the high saline brine area of 54 km2. The crystallised salt zone extends to a depth of more than 60 m whose estimated resource is about 300 million tonnes. The lake measures 10 by 7 km and has an area of liquid brine 54 km2. The maximum depth is 40 m, whereas the mean depth is 7.4 m, which makes for a water volume of 400 million cubic metres.

Salt production on a semi-commercial basis started in 1988 by small private enterprises. In 2004, after an initial low of 17,745 tonnes due to import duty of 53% imposed by Ethiopian exports, production increased and recorded a high of 110,000 tonnes in 2008.

While most commercial salt extractions are done from the huge deposits on the shores of the lake, there is also another novel way of extraction done by wading through the lake waters. The extracted salt is found in the form of spheres formed out of salt crystals and marketed in the name of Djibouti salts.

According to Wikipedia