oasis town, central Algeria, on the southern edge of the arid Tademaït Plateau. At the crossing of ancient trans-Saharan caravan routes, it was once an important trade link between northern and central Africa but has declined in modern times owing to high transportation costs and the exodus of workers to the developing gas fields 60 miles (100 km) southwest. Mainly visited by the nomadic Tuareg, it remains dependent upon the exportation of dates. The oasis has four red or violet clay brick ksars (walled villages), each with a citadel. Of these, the Ksar el-Arab oasis is inhabited by an entirely black African group. Palm groves and fruit and vegetable gardens surround the villages, irrigated by artesian wells and protected by hedges from the encroaching sand. Southwest of I-n-Salah (meaning “good well”) are two sebkhas (large, enclosed basins), fed in the winter by underground drainage. Pop. (latest est.) 20,733.