The 1851 Boundary Treaty established between Brazil and Uruguay as a result of the

Uruguayan Civil War The Uruguayan Civil War, also known in Spanish as the ''Guerra Grande'' ("Great War"), was a series of armed conflicts between the leaders of Uruguayan independence. While officially the war lasted from 1839 until 1851, it was a part of armed c ...

and conflicts with Brazil and Argentina; the result of the treaty was a step towards the acceptance of Uruguay's independence from neighboring territories.Parodi CA, 2002 "The Politics of South American Boundaries" Greenwood Publishing

Treaties

Uruguay rewarded Brazil's financial and military support by signing five treaties in 1851 that provided for perpetual alliance between the two countries. The

Treaty of Montevideo (1828) The Preliminary Peace Convention was a bilateral treaty signed on 27 August 1828 between the Empire of Brazil and the United Provinces of the Río de la Plata, after British mediation, that put an end to the Cisplatine War and recognized the in ...

confirmed Brazil's right to intervene in Uruguay's internal affairs. The treaties also allowed joint navigation on the

Uruguay River The Uruguay River ( es, Río Uruguay, ; pt, Rio Uruguai, ) is a major river in South America. It flows from north to south and forms parts of the boundaries of Brazil, Argentina, and Uruguay, separating some of the Argentine provinces of La M ...

and its tributaries, and tax exempted cattle and salted meat exports. The treaties also acknowledged Uruguay's debt to Brazil for its aid against the Blancos, and Brazil's commitment for granting an additional loan. In addition, Uruguay renounced its territorial claims to a border in the Ibicuí River and accepted the Quaraí River as northernmost border with Brazil, thereby reducing its area the size of the Cisplatina Province, and recognized Brazil's exclusive right of navigation in the

Lagoa Mirim Lagoon Mirim (Portuguese, ) or Merín (Spanish, ) is a large estuarine lagoon which extends from southern Rio Grande do Sul state in Brazil into eastern Uruguay. Lagoa Mirim is separated from the Atlantic Ocean by a sandy, partially barren isthm ...

and the Jaguarão River , the natural border between the countries. However, a dispute still exists in the vicinity of

Masoller Masoller is a village or populated centre of the Rivera Department in northern Uruguay, next to the ''de facto'' border with Brazil, in an area where that border is disputed. Geography The village is located on Route 30, on the tripoint with Sa ...

over which creek was meant to mark the border in that area. Uruguay also allowed Brazilians to legally own slaves in their properties despite the fact that after 1842 slavery wasn't legal in the country.

Notes

History of Uruguay Treaties of the Empire of Brazil Treaties of Uruguay Brazil–Uruguay border Brazil–Uruguay relations 1851 in Brazil 1851 in Uruguay 1851 treaties Boundary treaties {{treaty-stub