In the Battle of Yungay, Chile defeats an alliance between Peru and Bolivia.

The Battle of Yungay was the final battle of the War of the Confederation, fought on January 20, 1839, near Yungay, Peru. The United Restoration Army, led by Chilean General Manuel Bulnes, consisting mainly of Chileans and 600 North Peruvian dissidents, attacked the Peru-Bolivian Confederation forces led by Andrés de Santa Cruz in northern Peru, 200 kilometers (120 mi) north of Lima.

Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes Mountains and the Pacific Ocean. Chile had a population of 17.5 million as of the latest census in 2017 and has a territorial area of 756,102 square kilometers (291,933 sq mi), sharing borders with Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage to the south. The country also controls several Pacific islands, including Juan Fernández, Isla Salas y Gómez, Desventuradas, and Easter Island, and claims about 1,250,000 square kilometers (480,000 sq mi) of Antarctica as the Chilean Antarctic Territory. The capital and largest city of Chile is Santiago, and the national language is Spanish.

Peru, officially the Republic of Peru, is a country in western South America. It is bordered to the north by Ecuador and Colombia, to the east by Brazil, to the southeast by Bolivia, to the south by Chile, and to the south and west by the Pacific Ocean. Peru is a megadiverse country, with habitats ranging from the arid plains of the Pacific coastal region in the west, to the peaks of the Andes mountains extending from the north to the southeast of the country, to the tropical Amazon basin rainforest in the east with the Amazon River. Peru has a population of over 32 million, and its capital and largest city is Lima. At 1,285,216 km² (496,225 sq mi), Peru is the 19th largest country in the world, and the third largest in South America.