The San Juan River is the largest and most important river in the Mexican state of Nuevo León. The river feeds the El Cuchillo Dam, which provides the city of Monterrey with water. The San Juan River basin has a total surface area of 20,212 km² (7,803 square miles), or 31.5 percent of the state’s surface area. The San Juan River is a contributor to the Rio Bravo/Río Grande. It begins in Coahuila, flows through Nuevo León and into Tamaulipas, where it finally joins the Rio Grande near Camargo, Tamaulipas.
