濁水溪
Yunlin County is located in the central-south portion of western Taiwan and is at the northern tip of the Chianan Plain. The county is bordered by Nantou County to the east, the Taiwan Strait to the west, Chiayi County to the south separated by the Beigang River, and Changhua County to the north separated by the Zhuoshui River. Its widest distance from east to west is and from north to south is , with a total area of .