Rio de La Plata.

Rio de la Plata is an immense, funnel-shaped river estuary that runs from the juncture of two major rivers—the Uruguay and Paraná—to the South Atlantic Ocean. With Argentina on its south shore and Uruguay to the north, Rio de la Plata extends 186 miles (300 kilometers), broadening from 25 miles (40 kilometers) wide at the juncture to 124 miles (200 kilometers) wide near the sea. The immediate drainage basin covers 11,583 square miles (30,000 square kilometers). The combined hydrographic system of all three rivers extends from the subequatorial zone through the tropics, and includes part of Bolivia, Paraguay, Uruguay, Brazil, and Argentina.