Paraná (river, South America)

Paraná (river, South America), river in eastern South America, formed in south central Brazil by the confluence of the Rio Grande and Paranaíba River. It flows southwest across the eastern edge of the Mato Grosso and then forms the boundary between Brazil and Paraguay. The river sweeps west, forming part of the border between Paraguay and Argentina, to its confluence with the Paraguay River. The Paraná then runs south and east through Argentina until it unites with the Uruguay River to form the Río de la Plata estuary on the Atlantic Ocean. The river is about 2,800 km (1,740 mi) long, of which about 1610 km (about 1000 mi) are navigable by large ships. The Paraná, with its confluent rivers, forms one of the largest drainage systems in South America, second only to that of the Amazon River.