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 and South Peru—states that arose from the division of the Peruvian Republic due to the civil wars of 1834 and 1835 to 1836—as well as the Bolivian State.

The geographical limits of the Confederation varied over time, with Bolivia occupying and incorporating the 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 May 1, 1837, with the Pact of Tacna, its de facto establishment dated from October 28, 1836—with the end of the war between Salaverry and Santa Cruz—until August 25, 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.