The Pearl River, also known by its Chinese name Zhujiang (Chu Kiang) and formerly often known as the is an extensive river system in southern China. The name "Pearl River" is also often used as a catch-all for the watersheds of the Xi ("West"), Bei ("North"), and Dong ("East") rivers of Guangdong. These rivers are all considered tributaries of the Pearl River because they share a common delta, the Pearl River Delta. Measured from the farthest reaches of the Xi River, the Pearl River system is China's third-longest river, 2,400 kilometres (1,500 mi), after the Yangtze River and the Yellow River, and second largest by volume, after the Yangtze. The 409,480-square-kilometre (158,100 sq mi) Pearl River Basin (珠江流域) drains the majority of Liangguang (Guangdong and Guangxi provinces), as well as parts of Yunnan, Guizhou, Hunan and Jiangxi in China; it also drains northern parts of Vietnam's Northeast Cao Bằng and Lạng Sơn provinces.