Lake Assal is located in the middle of Djibouti, in a closed depression at the northern end of the Great Rift Valley. Situated in the Danakil Desert, it is bounded by hills on the western region. The lake lies at an altitude of 155 m (509 ft) below sea level, making it the lowest point of Africa.
Lake Assal is the most saline body of water on earth after Don Juan Pond with 34.8% average salt concentration (up to 40% at 20 m (66 ft) depth); higher than the 33.7% level in the Dead Sea. The dissolved salts include NaCl, KCl, MgCl2, CaCl2, CaSO4 and MgBr2, with NaCl dominating in Lake Assal and MgCl2 in the Dead Sea. The surface concentration of salts is 268.8 g/L for the Dead Sea and 276.5 g/L for Lake Assal; the concentration increases to 326.6 g/L at 50 m (160 ft) depth in the Dead Sea and to 398 g/L at 20 m (66 ft) depth in Lake Assal.