Paraguay River

Paraguay River, chief tributary of the Paraná River, in South America. It rises in the Mato Grosso region of western Brazil and flows about 1,300 mi (2,090 km) southward to join the Paraná near Corrientes. Part of the Río de la Plata system, its chief branches, the Pilcomayo and the Bermejo, enter from the west. It is mostly navigable; Asunción, Paraguay, is its chief port.