The 1866 treaty established the first formal border between Chile and Bolivia at the 24th parallel, creating a shared tax zone that ultimately contributed to the War of the Pacific.
Key Facts
- Signing date
- August 10, 1866
- Border established
- 24° South parallel
- Chilean signatory
- Álvaro Covarrubias, Foreign Affairs Minister
- Bolivian signatory
- Juan R. Muñoz Cabrera, Plenipotentiary
- Superseded by
- New boundary treaty of 1874
- Subsequent conflict
- War of the Pacific began 1879
By the Numbers
Location
Cause → Event → Consequence
Increasing border tensions between Chile and Bolivia since the 1840s over their undefined frontier remained unresolved, though both nations had fought together against Spain in the Chincha Islands War (1864–65). This shared military experience under Bolivian President Mariano Melgarejo and Chilean President José Joaquín Pérez created diplomatic conditions for a negotiated settlement.
On August 10, 1866, Chile and Bolivia signed the Boundary Treaty in Santiago, drawn up by Chilean Foreign Minister Álvaro Covarrubias and Bolivian Plenipotentiary Juan R. Muñoz Cabrera. The treaty fixed the border at the 24th parallel and established a joint 'Mutual Benefits zone' with shared tax collection and preferential trade terms for goods from both countries.
Both nations soon grew dissatisfied with the arrangement. Bolivia and Peru concluded a secret anti-Chile alliance in 1873, and a clarifying protocol was never ratified by Bolivia. A revised treaty in 1874 replaced the original, but Bolivia's violation of it in 1878 provided the immediate trigger for the War of the Pacific, which began in 1879.
Political Outcome
Border fixed at 24° South parallel; Mutual Benefits zone with shared tax collection established between Chile and Bolivia
Undefined border with growing tensions between Chile and Bolivia since the 1840s
Formal border at 24th parallel with a joint tax zone, though instability persisted and led to the 1874 treaty and eventual War of the Pacific