the longest and most important river of Algeria. Its farthest tributary, the Sebgag River, rises in the Amour ranges of the Saharan Atlas Mountains near Aflou. Crossing the Hauts Plateaux for most of the year as a chain of marshes and muddy pools, the river loses most of its water but is replenished by a stream near Chabounia, the Nahr Ouassel River. The Chelif then turns abruptly north to rush through a deep gorge in the Tell Atlas Mountains between Ksar el-Boukhari (formerly Boghari) and Djendel (formerly Lavigerie). Below Oued Chorfa (formerly Dollfusville) the river swings to the west, flowing for about 145 miles (230 km) parallel with the coast in a depression (the Chelif plain) between the Dahra Massif, Mount Zaccar Rherbi, and the Tell Atlas. The river reaches the Mediterranean about 8 miles (13 km) north of Mostaganem.

The Chelif is unnavigable throughout its 450-mile (725-kilometre) length, and its flow is irregular, the maximum being November to March. The Chelif plain receives only moderate, undependable rainfall (average, 16 inches 【400 mm】 annually), and evaporation is intense. The lower reaches of the river's basin are, however, cultivated with the aid of irrigation. Three main dams have been constructed on the Chelif system at Ksar el-Boukhari (1932), Ech-Cheliff (formerly El-Asnam; 1932), and El-Khemis (1939). Cereals, oranges, and grapes are the principal crops, and there is minor cultivation of cotton around the town of Ech-Cheliff.