Treaty of Ancón
The Treaty of Ancón was signed by Chile and Peru on 20 October 1883, in the Ancón District near Lima. It was intended to settle the two nations' remaining territorial differences at the conclusion of their involvement in the War of the Pacific and to stabilise post-bellum relations between them.
Under the treaty's terms, Chile gained control over Tarapacá. Chile was also to retain the conquered provinces of Tacna and Arica for ten years, after which their fate was to be decided by a plebiscite. The plebiscite was never held.
Finally, in 1929, through the mediation of the United States under President Herbert Hoover, an accord was reached. Under the Tacna-Arica compromise, Chile kept Arica, while Peru regained Tacna and received USD $6 million indemnity and other concessions.
Another important provision in the treaty said that Chile could not cede sovereignty of former Peruvian territories to other nations without asking Peru first. The Chapter has been invoked once, during the Chilean proposal of 1975 that offered Bolivia sovereignty over some minor ports. The Peruvian government rejected the proposed land swap.
