The Uruguay River flows from north to south and makes boundary with Brazil, Argentina, and Uruguay, separating some of the Argentine provinces of the Mesopotamia from the other two countries. It passes between the states of Santa Catarina and Rio Grande do Sul in Brazil; forms the eastern border of the provinces of Misiones, Corrientes, and Entre Ríos in Argentina. The river measures about 1,600 kilometres (990 mi) in length and starts in the Serra do Mar in Brazil, where the Canoas River and the Pelotas River are joined, at about 200 m above mean sea level. In this stage the river goes through uneven, broken terrain, forming rapids and falls.
Its course through Rio Grande do Sul is not navigable. Together with the Paraná River, the Uruguay forms the Río de La Plata estuary. It is navigable from around Salto Chico. The river is crossed by five international bridges (from north to south): Integration Bridge and Paso de los Libres-Uruguaiana International Bridge, between Argentina and Brazil; and the Salto Grande Bridge, General Artigas Bridge and Libertador General San Martín Bridge between Argentina and Uruguay.