According to Yanomami oral tradition and the earliest documents mentioning this indigenous group, the historical center of their habitat is located in the Parima mountain range, the watershed between the upper Orinoco and the right bank affluents of the Rio Branco. This is still the most densely populated area of their territory. The movement of dispersion of the Yanomami peoples from the Parima range in the direction of the surrounding lowlands probably began in the first half of the 19th century, after the colonial penetration into the regions of the upper Orinoco and the Rio Negro and Rio Branco in the second half of the 18th century. The contemporary configuration of Yanomami lands has its origins in this ancient migratory movement.

This geographical expansion of the Yanomami was possible, from the start of the 19th century until the start of the 20th century, due to dramatic demographic growth. A number of anthropologists believe that this population expansion was caused by economic transformations induced by the acquisition of new plants for cultivation and metal tools through exchange and warfare with neighboring indigenous groups (Carib, to the north and east; Arawak, to the south and west), who in turn maintained direct contact with the colonial frontier. The progressive emptying of the territory of these groups, decimated by contact with the regional white society throughout the 19th century, ended up also favoring the process of Yanomami expansion.