Peru–Bolivian Confederation

The Peru–Bolivian Confederation (Spanish: Confederación Perú-Boliviana) was a short-lived state that existed in South America between 1836 and 1839. The country was a loose confederation made up of three states: North Peru, South Peru, and the Bolivian Republic. North Peru and South Peru had emerged from the division of the Peruvian Republic due to the Peruvian Civil War of 1834 and the Salaverry-Santa Cruz War of 1835-6.

The geographical limits of the Confederation varied over time, with Bolivia occupying and incorporating certain disputed territories in northern Argentina in 1838. It also possessed de facto autonomous indigenous territories, such as Iquicha, all under the supreme command of Marshal Andrés de Santa Cruz, who assumed the position of Supreme Protector in 1836, while he was president of Bolivia.

Although its institutional creation arose on 1 May 1837, with the Pact of Tacna, its de facto establishment dated from 28 October 1836, with the end of the Salaverry-Santa Cruz War, and lasted until 25 August 1839, with its dissolution proclaimed by General Agustín Gamarra, the Peruvian restorationist president who declared war against the Confederation, supported by the United Restoration Army headed by himself and Chilean Manuel Bulnes—formerly the Restoration Army of Peru—made up of Peruvian and Bolivian opponents of the Confederation, as well as the governments and armies of Chile and Argentina. Both Chile and Argentina opposed the Confederation as a potential military and economic threat, and for its support for dissidents in exile.

Argentina and Bolivia reached an agreement after their war over Tarija, and the Confederate Army was ultimately defeated by the United Restoration Army in the 1839 Battle of Yungay, which put an end to the War of the Confederation. Historian Jorge Basadre frames the confederation as part of a period of "determination of the nationalities" in western South America.