SON RIVER

also spelled Sone, principal southern tributary of the Ganges River, rising in Madhya Pradesh state, central India. It flows north past Manpur and then turns northeast. The river cuts through the Kaimur Range and joins the Ganges above Patna, after a 487-mile (784-kilometre) course. The Son valley is geologically almost a continuation of that of the Narmada River to the southwest. Largely forested, it is sparsely populated. The valley is bordered by the Kaimur Range (north) and the Chota Nagpur plateau (south). The river's flow is seasonal, and the Son is unimportant for navigation. Dams have been constructed on some of its tributaries, and at Dehri, Uttar Pradesh state, are the headworks of the Son Canal system.