The Shoshone of this area were poorer in horses than the buffalo hunters, but they did possess some. The valleys of the Boise, Payette, and Weiser evidently afforded adequate grazing for small herds, and the natives enjoyed a greater mobility than did their neighbors to the northeast and southeast. The resulting ease of communication would perhaps be conducive to band organization, but neither living informants nor historical sources offer any confirmation of this. That such sociopolitical groups did exist is suggested by mention of chiefs, but the groups did not have clearly defined territories which excluded other peoples, and they could only have been most loosely organized.
This area includes all of Idaho south of the Sawtooth Mountains between American Falls and the Bruneau River. It has been seen that the area of the Boise, Payette, and Weiser rivers was entered regularly by populations that did not customarily winter there; this is true also of the area of the middle Snake, and to a much greater degree. First, the salmon run did not extend above Shoshone Falls, and the population living upstream from that point resorted regularly to favored fishing places below the Falls. Second, the prairies about the locale of present-day Fairfield, Idaho, were the richest camas-root grounds in this section of the Basin-Plateau area and large numbers of Indians convened every summer to gather the roots. Historical sources testify to the numbers of Indians found in the area during certain times of the year, but it is usually impossible to determine the geographical locus of these people during the remainder of the year.
Travelers observed small, impoverished groups of Indians and also larger camps of mounted people. Near Glenn's Ferry, Idaho, Stuart on August 23, 1812, noted (1935, p. 108):
... a few Shoshonie (or Snake) Camps were passed today, who have to struggle hard for a livelihood, even though it is the prime of the fishing season in the Country.
Stuart encountered some 100 lodges of Shoshone fishing at Salmon Falls (p. 109). In 1826 Peter Skene Ogden met a camp of 200 "Snakes" bearing 60 firearms and a quantity of ammunition at Raft River, above the limit of the salmon run (Ogden, 1909, p. 357). In October of the following year he visited Camas Prairie, the camas grounds in the vicinity of Fairfield, and noted a pattern of movement that is still reported by informants (p. 263):