Which river is the second-longest in South America after the Amazon?

The Paraná River is the second-longest river in South America after the Amazon.

The Paraná flows for roughly 4,880 kilometers through Brazil, Paraguay, and Argentina. It begins in southern Brazil, where the Rio Grande and Paranaíba meet, then travels generally southward toward the Río de la Plata estuary and the Atlantic Ocean.

The river is part of the Plata Basin, one of South America’s major drainage systems. Its waters support cities, farms, navigation, fisheries, and large hydroelectric projects, including the Itaipu Dam on the Paraná between Brazil and Paraguay. The river also forms or follows sections of international borders.

A common source of confusion is the distinction between a single river and a combined river system. Some rankings count the Paraná together with connected tributaries such as the Paraguay River, while others list the Paraná itself. Under the usual standalone-river comparison, it is South America’s second-longest river, behind the Amazon. The Orinoco, São Francisco, and Magdalena are shorter.