Before the founding of San Martín de los Andes, the valley of Chapelco was sparsely populated by indigenous Puelches who used it as a refuge during the harsh winters of the zone. The Puelches had, since colonial times, engaged in trade with the Huilliches on the eastern slope of the Andes through various mountain passes. Puelches raised horses on the eastern slopes of the Andes and traded them for weapons and alcoholic beverages becoming one of the main food providers of the isolated exclave of Valdivia. The Argentine and Chilean military campaigns; the conquest of the Desert and the occupation of Araucanía; in the second half of the 19th century bought a definitive end to this trade.