Alto Bio Bío, differently than how it happens now, during centuries was marked for silence, or better said, a simmering activity that did not arrive to the ears of those in the valley.

The small amount of literature that exists barely mentions the zone and the indigenous population, los pehuenches. The more serious and recent approximations began being written in small chapters around the middle of the 18th century. The installation of a fortified line, associated with the evangelical activities of the catholic missionaries, that were from Rucalhue, were passing through Villucura and Santa Barbara. The origin of the indigenous is one motive of several theories, however there is nothing concrete.

More causes in the Antuco zone (several dozen kilometers north) where strong commercial activity was realized between the criollos and pehuenches. The travel journals of the polish naturalist Ignacio Domeyko⁷ and the Bavarian artist Mauricio Rugendas relate who took the first pictures of the indigenous population.

As we were saying, the tranquility of the zone was interrupted by the Chilean army's manhunts at the beginning of the 19th century. The manhunts of the Chilean army montoneros⁸, a leftist urban guerrilla group, that were still loyal to the Spanish Kingdom or of the rustling bandits that devastated the homes of the criollos in the plains (the Pincheira brothers wrote a few of the chapters in Alto Bio Bío).

One hundred years later they went to the events of Ránquil, the eastern most part of the mountain range, where a national working revolt took place. This took place in this zone, with a tragic number of deaths.

According to the 2002 census of the National Statistics Institute, Alto Bío Bío had 7,027 inhabitants; of these, 1,094 (15.6%) lived in urban areas and 5,933 (84.4%) in rural areas. The population grew by 31.2% (1,671 persons) between the 1992 and 2002 censuses.

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Wikipedia