The widest river in the world is Río de la Plata or River Plate, formed by the confluence of the Uruguay and Paraná rivers, and it empties into the Atlantic Ocean. It flows through Brazil, Bolivia, Paraguay, Uruguay and Argentina.
The Río de la Plata is considered by some geographers as a gulf or a marginal sea of the Atlantic Ocean. It is generally considered a river with a maximum width of 230 kilometres at its mouth, and an estuary that drains the second largest basin in South America, after the Amazon basin, and the fifth largest in the world. Its drainage basin plus the basins of its tributaries add up to some 3,200,000 square kilometres, about a fifth of the surface area of the American continent.
The system consists primarily of the Paraná and Uruguay rivers, which contribute 97% of the total discharge volume, with annual average discharges of 16,000 and 4,000 m3/s respectively.