Zona Sur (Southern Zone) is one of the five natural regions on which CORFO divided continental Chile in 1950. Its northern border is formed by the Bío-Bío River, which separates it from the Central Chile Zone. The Southern Zone borders the Pacific Ocean to the west, and to the east lies the Andean mountains and Argentina. Its southern border is the Chacao Channel, which forms the boundary with the Austral Zone. While the Chiloé Archipelago belongs geographically to the Austral Zone in terms of culture and history, it lies closer to the Southern Zone.