The Syun (Bashkir: Сөн, Sön; Russian: Сюнь; Tatar: Сөн, Sön) is a river in Bashkortostan and Tatarstan, Russian Federation, a left-bank tributary of the Belaya (Kama basin). It is 209 kilometres (130 mi) long,^[1] of which 74 kilometres (46 mi) are in Tatarstan. Its drainage basin covers 4,500 square kilometres (1,700 sq mi).^[1] Major tributaries in Tatarstan are Kalmiya, Sikiya, Terpelya, Bezyada, and Sharan in Bashkortostan. The maximal water discharge is 655 cubic metres per second (23,100 cu ft/s) (1979), and the maximal mineralization 500 to 1000 mg/L. Average sediment at the mouth per year is 120 millimetres (4.7 in). Drainage is regulated. Since 1978 it is protected as a "natural monument of Tatarstan".^[2]