Ended the War of the Pacific between Chile and Peru, transferring Tarapacá permanently to Chile and leaving Tacna–Arica unresolved until 1929.
Key Facts
- Date signed
- 20 October 1883
- Signing location
- Ancón, near Lima, Peru
- Territory permanently ceded to Chile
- Tarapacá
- Tacna–Arica provisional retention
- 10 years, pending plebiscite never held
- Tacna–Arica final resolution
- 1929, Treaty of Lima
- Peru's indemnity (1929 settlement)
- 6,000,000 USD
By the Numbers
Location
Cause → Event → Consequence
The War of the Pacific (1879–1884) pitted Chile against Peru and Bolivia over disputed nitrate-rich territories. Chile's military victories left it in occupation of several Peruvian provinces, including Tarapacá, Tacna, and Arica, creating the need for a formal diplomatic settlement to end hostilities.
On 20 October 1883, Chile and Peru signed the Treaty of Ancón, by which Peru permanently ceded the province of Tarapacá to Chile. Chile was additionally granted a ten-year administrative occupation of Tacna and Arica, after which a public plebiscite was to determine their final sovereignty.
The treaty ended Peru's formal involvement in the War of the Pacific but left the Tacna–Arica question unresolved for decades. The promised plebiscite was never held, and the dispute persisted until the 1929 Treaty of Lima, mediated by the United States, awarded Arica to Chile and returned Tacna to Peru along with a $6 million indemnity.
Political Outcome
Peru permanently ceded Tarapacá to Chile; Tacna returned to Peru in 1929, Arica retained by Chile under the subsequent Treaty of Lima.
Peru held sovereignty over Tarapacá, Tacna, and Arica prior to Chilean military occupation.
Chile gained Tarapacá outright and eventually Arica; Peru recovered Tacna and received monetary compensation in 1929.