Uruguay River, << YUR uh `gway` or `oo` roo GWY, >> is part of the great Paraná and La Plata river system of South America. The Uruguay rises in the state of Santa Catarina in southern Brazil. The river flows west and then south to the bay of the Río de la Plata. The Uruguay is about 1,000 miles (1,600 kilometers) long. It forms part of the boundary between Brazil and Argentina, and the entire boundary between Uruguay and Argentina. Before it joins the Río de la Plata, the Uruguay River becomes a lake from 4 to 7 miles (6 to 11 kilometers) wide.
