The Uruguay River (Spanish: Río Uruguay, Spanish pronunciation: [uɾuˈɣwai]; Portuguese: Rio Uruguai, Portuguese pronunciation: [uɾuˈɡwaj]) is a river in South America. It 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; and makes up the western borders of the departments of Artigas, Salto, Paysandú, Río Negro, Soriano, and Colonia in Uruguay.
Uruguay i//, officially the Oriental Republic of Uruguay and sometimes called the Eastern Republic of Uruguay (Spanish: República Oriental del Uruguay, pronounced: [reˈpuβlika oɾjenˈtal del uɾuˈɣwaj]), is a country in the southeastern part of South America. It is home to 3.3 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area. An estimated 88% of the population is of European descent. With an area of approximately 176,000 square kilometres (68,000 sq mi), Uruguay is the second-smallest nation in South America by area, after Suriname.