The Boundary Treaty of 1881 (Spanish: Tratado de Límites de 1881) between Argentina and Chile was signed on 23 July 1881 in Buenos Aires by Bernardo de Irigoyen, for Argentina, and Francisco de Borja Echeverría, for Chile, with the aim of establishing a precise border between the two countries based on the uti possidetis juris principle. Despite dividing largely unexplored lands, the treaty laid the groundwork for nearly all of Chile's and Argentina's 5600 km current border.
