Gran Chaco
Collier's New Encyclopedia (1921)
an extensive central tract of South America, extending from the S. tropic to 29° S. lat., and bounded on the E. by the Paraguay and Paraná, and on the W. by the Argentine provinces of Santiago del Estero and Salta; area, about 180,000 square miles. The portion S. of the Pilcomayo belongs to Argentina, and the remaining third to Paraguay; but the possession of the upper section of the Pilcomayo is disputed by Bolivia. The country rises gradually from the Paraná toward the N. W. as far as 25° 40′ S. lat., when it dips to the valley of the San Francisco-part of a great depression extending through Bolivia nearly to the frontier of Peru, and subject to annual inundations. The Chaco is watered principally by two long, narrow, and tortuous streams, the Bermejo and the Pilcomayo, flowing S. E. in courses generally parallel, and about 180 miles distant from each other. The bed of the Bermejo oscillates backward and forward, and in 1870-1872 the river opened up a new channel (known as the Teuco) for nearly 200 miles. The most N. part of the Chaco is an extremely arid zone, but the banks of the upper Pilcomayo are fertile and its sands auriferous, while S. of the Bermejo the primeval forest extends into Salta. Much of the region is of modern alluvial formation, and exceedingly fertile. Since 1537, when the first explorer, Captain Juan de Ayolas, marched with 250 men into the wilderness from which none ever returned numerous expeditions have been sent out from the surrounding countries; but the savage tribes, swamps, lagoons, and floods defeated all early attempts to open up the country. In 1884 garrisons were established along the Bermejo, and since 1885 permanent settlements have been made.
What Has Changed in the Last Century
Collier's noted in 1921 that Bolivia disputed possession of the upper Pilcomayo; that dispute became the Chaco War of 1932-35, the bloodiest inter-state conflict in twentieth-century South America, in which Bolivia and Paraguay lost roughly 100,000 men between them. The 1938 peace treaty gave Paraguay the bulk of the contested Chaco while Bolivia kept a corridor to the Paraguay River, and the boundaries the article calls unsettled have been fixed ever since. The "savage tribes, swamps, lagoons, and floods" that Collier's said had defeated settlement no longer hold the region: Mennonite colonies established from 1927 grew into towns such as Filadelfia, and since the late twentieth century cattle ranching and soy have made the Gran Chaco one of the fastest-disappearing dry forests on earth. Indigenous peoples the article dismissed in a phrase — Wichí, Nivaclé, Ayoreo and others — are now recognised landholders, and some Ayoreo groups remain uncontacted.
Written for this edition, 2026.