The Xi River (/ʃiː/; Chinese: 西江) or Si-Kiang is the western tributary of the Pearl River in southern China. It is formed by the confluence of the Gui and Xun Rivers in Wuzhou, Guangxi. It originates from the eastern foot of the Maxiong Mountain in Qujing City, Yunnan Province. Then it flows east through Guangdong, and enters the Pearl River Delta just east of the in Zhaoqing. The main branch of the Xi River flows southeast through the delta entering the South China Sea at , just west of Macau. The major cities along the Xi include Wuzhou, Zhaoqing, and Jiangmen.