The Yu River (郁江 or 鬱江) (also called the Siang River) is a river in the south of China. It rises in two branches - the Zuo River (左江) and the You River (右江). The You flows roughly south-east from its source close to Baise City in Guangxi. The Zuo flows north-east from its sources in Vietnam: Peng River (Vietnamese: Bằng Giang) and Kỳ Cùng River (totally in Vietnam). They meet just west of Nanning. From here, it is known as the Yong Jiang (邕江) as it flows through Nanning before becoming the Yu . The Yu itself runs roughly northeast before joining the Qian River (黔江) at Guiping to form the Xun River.
The Yu River is a tributary of the Xi River. Yu originates in the southeastern region of the Yunnan province. Its 400-mile-long course lies mostly in the Guangxi province. The Yu River is one of the most important rivers of southern China for navigation.