evidence: However, the treaty did not explicitly state the ownership of a small section near Masoller known as Rincon de Artigas, whose sovereignty has been challenged by the two countries. Currently, the controversial portion is under the administration of Brazil. Argentina is one of the two countries that border Uruguay and is situated west of the country. The two countries share a long land border, which stretches about 360 miles in length, making it the shortest of Uruguay’s international borders. The tri-point connecting Uruguay, Argentina and Brazil represent the start of the border, from where it follows the Uruguay River until it meets the confluence of the Rio de la Plata and River Parana. Buenos Aires, Corrientes, and Entre Rios are the three provinces in Argentina touched by the border, while in Uruguay the border touches six departments, which are the Rio Negro, Artigas, Colonia, Paysandu, Soriano, and Salto. The border has always been defined by the Uruguay River, and predates the establishment of the Republic of Uruguay, as it separates the Viceroyalty of Rio de la Plata of the Eastern Band. The two countries have clashed in the past over a territorial dispute concerning the building on the Uruguay River of pulp mills. The issue strained diplomatic relations between the two bordering countries and threatened to sever the long-standing socioeconomic corporation between the two countries.