Tacna–Arica dispute

The Tacna-Arica dispute was a territorial disagreement between Peru and Chile that stemmed from the War of the Pacific (1879-1883). This conflict, primarily over control of valuable nitrate-rich lands in the Atacama Desert, resulted in Chile's victory over Peru and its ally Bolivia.12

Following the war, the Treaty of Ancón in 1883 awarded Chile possession of the province of Tarapacá and administrative control over the provinces of Tacna and Arica for ten years. After this period, a plebiscite was to determine the sovereignty of Tacna and Arica. However, disagreements over the terms of the plebiscite led to decades of diplomatic tension, known as the "Question of the Pacific". A final resolution was reached in 1929 through U.S. mediation, with Chile retaining Arica and Peru regaining Tacna, along with an indemnity and other concessions.2314