The Zhuoshui River (Chinese: 濁水溪), also spelled Choshui or Jhuoshuei River, is the longest river in Taiwan, with a total length of 203 km (126 mi). It flows from its source in Nantou County up to the western border of the county, subsequently forming the border between Yunlin County and Changhua County. The river serves as an unofficial boundary between the north and south of Taiwan.
The river is dammed in its upper reaches by the Wushe and Wujie Dams, and further downstream by the Jiji Weir. In recent years, the environment surrounding the river has been seriously degraded both by the construction of a dam across the river at Jiji and by the ongoing activities of the concrete industry.