Río Biobío
South of the Central Andes, the Alto Bío Bío area covers the Andean surroundings of the upper Bío Bío River, Chile's second largest river, in the Bío Bío Region. The area is a center for the indigenous Pehuenche people and currently contains two Sendero de Chile trails, as well as other important parks such as Ñuble National Reserve.