Uruguay (river)

Uruguay (river), central South America, rising in the coastal range of southern Brazil. It flows west on the boundary between the states of Santa Catarina and Rio Grande do Sul, forming with the River Paraná the River Plate. Separating Brazil and Uruguay from Argentina, it has a course of about 1,600 km (1,000 mi). It is navigable for large steamers to Concepción del Uruguay, Argentina, and Paysandú, Uruguay, and for smaller vessels to Concordia in Argentina and Salto in Uruguay, about 320 km (200 mi) from its mouth, where navigation is halted by a cataract.