evidence: A triangular region, named Rincão de Artigas in Portuguese, is controlled by Brazil and claimed by Uruguay. The dispute is due to a disagreement as to where a stream known as Arroyo de la Invernada begins and where it ends. Brazilian Island, a river island at the junction of the Quaraí River and the Uruguay River on the border between Argentina, Brazil, and Uruguay is claimed by both Uruguay and Brazil. Brazil has de facto control of it. [...] Brazilian Island: The tripoint of Brazil, Argentina, and Uruguay. Due to a border dispute between Brazil and Uruguay over the river island, the exact position of the tripoint is in dispute.