The Battle of Chacabuco, fought during the Chilean War of Independence, occurred on February 12, 1817. The Army of the Andes of the United Provinces of the Río de la Plata, led by Captain–General José de San Martín, defeated a Spanish force led by Rafael Maroto. It was a defeat for the Captaincy General of Chile, the royalist government established after the division of the Viceroyalty of Peru.

The Chiloé Archipelago is a group of islands lying off the coast of Chile, in the Los Lagos Region. It is separated from mainland Chile by the Chacao Channel in the north, the Sea of Chiloé in the east and the Gulf of Corcovado in the southeast. All islands except the Desertores Islands form Chiloé Province. The main island is Chiloé Island. Of roughly rectangular shape, the southwestern half of this island is a wilderness of contiguous forests, wetlands and, in some places, mountains. The landscape of the northeastern sectors of Chiloé Island and the islands to the east is dominated by rolling hills, with a mosaic of pastures, forests and cultivated fields.