The Río de la Plata Basin is the name given to the 4 144 000 km2 hydrographical area that covers parts of Argentina, Brazil, Bolivia, Paraguay and Uruguay. It is one of the largest river basins on Earth.

The precipitation falling within this area is collected by several rivers to finally reach the Río de la Plata (or River Plate; River of Silver in Spanish), many of them through the Paraná River and the Uruguay River, its two most important tributaries. These rivers include the Paraguay, Pilcomayo, Bermejo, Salado, Carcarañá, Tercero, Tietê, Cuarto, Iguazú, Salado del Sur, Gualeguay, Nogoyá, Mocoretá, Gualeguaychú, Miriñay, Aguapey, Negro, Guaycurú, San Javier, Guayquiraró and Samborombón.