Conquest of the Desert
In 1867, Law 215 had been promulgated, ordering the national government to expand the southern frontier as far as the Río Negro; it could not be implemented because of the Paraguayan War.
The offensive against the indigenous peoples had to wait until 1872; when signs appeared that attacks on their tolderías were being planned, the principal cacique Calfucurá ordered the largest malón in history, which—in March of that year—attacked and looted much of central Buenos Aires Province. A rapid response by General Ignacio Rivas, with support from Ranquel allies, allowed a complete victory in the Battle of San Carlos de Bolívar.
From then on, aided by Calfucurá's death, the national government began a series of frontier advances, especially in western Buenos Aires. At the beginning of 1876, the caciques Juan José Catriel and Manuel Namuncurá—Calfucurá's son and successor—launched another major malón on the south of Buenos Aires Province.
Minister Alsina then launched an aggressive campaign to occupy the west of the province: throughout 1876 he advanced with five parallel columns against the principal indigenous forward settlements, occupying them. To prevent further incursions, he ordered the construction of the so-called Zanja de Alsina: a line of fortines linked by a trench 3.50 metres wide and 2.60 metres deep, which served as a boundary for unconquered territories over 374 km between Italó—in southern Córdoba—and Nueva Roma, a short distance from Bahía Blanca.
Without realizing it, by taking the western lagoons Alsina destroyed the foundations of indigenous prosperity, since the occupied lagoons were used to keep their horses fed and to fatten the cattle driven off in malones; on the other hand, in those years the indigenous population was struck by a smallpox epidemic that cost thousands of lives.
After Alsina's death, Avellaneda appointed General Julio Argentino Roca as his replacement, who had criticized Alsina's supposedly defensive stance. Unlike his predecessor, who had attempted to integrate the indigenous peoples into Western civilization, Roca maintained that the only solution to the threat they represented was their subjugation, expulsion, or elimination. These groups came from the Araucanía region and sought to steal cattle in order to sell them in Chile, which heightened the perception of danger and justified the harsh measures proposed by Roca. On the basis of that premise, he proposed a bill to occupy all indigenous territory as far as the Negro and Neuquén rivers within two years. The law was passed on 4 October 1878, granting 1,700,000 pesos to the project, when the plan was already underway.
Throughout 1878, successive offensives were launched against indigenous positions, causing hundreds of casualties among Namuncurá's forces and the capture of the feared Ranquel caciques Pincén, Catriel, and Epumer. Some 4,000 indigenous people—mostly women and children—were captured in these campaigns. In addition, the malones left a significant toll of kidnappings, with numerous settlers, especially women and children, taken captive by indigenous groups. The attacks resulted in the deaths of many citizens, defenders, and Tehuelches living peacefully in Patagonia, although exact figures vary by source. As for cattle theft, it is estimated that thousands of head were stolen during these raids, with each malón taking between 40,000 and 200,000 head of cattle.
On 11 October 1878, by means of Law 954, the Governorate of Patagonia was created, with its seat at Mercedes de Patagones, now Viedma, and Colonel Álvaro Barros as its first governor; its jurisdiction extended as far as Cape Horn.
In April 1879 the final attack was launched: five divisions totaling 6,000 men—including 820 allied indigenous troops—advanced in a fan formation toward the Negro River; Minister Roca celebrated on 25 May on Choele Choel Island. According to the Report presented by the Minister of War, 1,313 spear-bearing Indians were killed and 1,271 taken prisoner; five principal caciques were taken prisoner and one was killed; 10,513 de chusma Indians—women and children—were taken prisoner, and another 1,049 were reduced.
