By 1810, the early explorations of Thompson, Lewis and Clark, and others bore fruit in the commercial exploitation of the far Northwest. The fur trade had already reached the Plains and the Rockies in Canada, and a fierce competition was being waged by the Hudson's Bay Fur Company and the North West Company for the patronage of the Indians there. The British interests pushed southward from Canada, and in 1809 David Thompson established North West Company trading posts on Pend Oreille Lake at the mouth of the Clark Fork River and another farther up that stream within the borders of present-day Montana. At the same time, American traders were pushing westward, and Andrew Henry crossed the Continental Divide to locate his trading post on Henry's Fork of the Snake River in 1810. Also, John Jacob Astor's Pacific Fur Company established the ill-fated Astoria post at the mouth of the Columbia River in 1811. Although this particular American enterprise foundered, Manuel Lisa, the guiding spirit of the Missouri Fur Company, penetrated the Missouri River country and founded a post on the Yellowstone River at the mouth of the Big Horn in 1807. From this point his trappers spread into the near-by mountain country. The most famous of these mountain men was John Colter, who trapped the country of the Blackfoot and Crow and discovered Yellowstone Park.
The northern Plains and Rockies had thus been entered and partially explored by 1812, and increasing numbers of trappers poured into the new Louisiana Purchase and the lands beyond. Astor stepped into the territory of the Missouri Fur Company after Lisa's death in 1820, and in 1822 the Western Division of his American Fur Company was established. Fort Union was built on the upper Missouri to serve as the headquarters of Astor's mountain realm, and steamboats served the post after 1832. A decade before this date, the Rocky Mountain Fur Company was established, and in the following year, 1823, the company's trappers began to exploit intensively the drainages of the Wind River and the upper Snake and Green rivers. The Rocky Mountain Company established a new pattern of trading. Eschewing the rigid and hierarchical organization of the British companies, it relied mainly upon the services of free trappers, who gathered once a year at agreed places to meet the company's supply trains. These gatherings, the famous trappers' rendezvous, were held in the summer at various places in Shoshone country—Pierre's Hole, Cache Valley, or the Green River.
The trappers of the Rocky Mountain Company and later of the American Fur Company invested every fastness of the Shoshone hunting grounds in relentless pursuit of the beaver, the vital ingredient of the gentleman's top hat. The intense traffic in the Shoshone region was abetted by the penetration of the Snake River drainage by Donald McKenzie of the North West Company, beginning in 1818, and later by Peter Skene Ogden, under the auspices of the Hudson's Bay Company. The climax of fur trapping came in the middle of the decade of the 1830's, for at the peak of activity the commerce collapsed. Competition between the various trading companies had been ruinous, the streams had been thoroughly trapped out, and the beaver hat went out of fashion. By 1840, the fur trade in the northwest part of the United States was substantially ended.
During the period 1810-1840 the Shoshone and their neighbors lost the isolation they had formerly enjoyed and came into close contact with the whites. The latter were of a different type than those with whom the Indians later had to deal. They lived off the land, but at the same time they did not dispossess the Indians from their hunting grounds. Although there were sporadic clashes between the trappers and Shoshone and Bannock groups, relations were largely amicable. The trappers married Indian women and lived for varying periods with Indian bands. And both found a common enemy in the Blackfoot. The Indians also traded with the whites and through them obtained firearms, iron utensils, and other commodities, including the raw liquor of the frontier. But the American companies apparently did not attempt to utilize Indian labor to the same extent as did the British companies. The bulk of the fur yield was garnered by the free trappers and not by Indians. The Shoshone traded some small animal furs and buffalo robes to the whites, but they also sold meat, horses, and other commodities. They never became fur trappers in the same complete way as did the northern Algonkian and Athapaskan peoples.
After the decline of the fur trade, the Shoshone did not return to their pristine state of isolation. In the early 1840's, shortly after the debacle of the beaver trade, a strong surge of immigration from the States to Oregon began. The road to Oregon followed trails well marked by the trappers. It ascended the Platte and North Platte rivers and thence to the South Pass via the Sweetwater. From South Pass the trail went down to Fort Bridger, established in 1843, and then turned to the northwest and Fort Hall on the Snake River. The California branch of the trail bent southwest before reaching Fort Hall and descended the Humboldt River. The initial trickle of emigration grew into a great stream, and after the discovery of gold in California the Oregon Trail became a great highway to the west.
Busy though the trail was, the emigrants had but a single purpose. This was to cross the "Great American Desert," or the Plains, and reach the promised lands of the Pacific Coast. Except for the immediate environs of the emigrant road, the mountain country contained fewer whites than during the previous decade. This situation soon changed. In 1847 the Mormon migration reached the Salt Lake Valley, and during the following years Mormons settled adjacent areas of Wyoming and Idaho. Miners poured into the Sweetwater River country of Wyoming in the 1860's and in 1869 Fort Stambaugh was established at South Pass to protect them and the emigrant road. This route, however, had already seen its greatest days, for the Central Pacific Railroad was completed in the same year.
The Wild West was substantially ended by this date, and the Shoshone signed treaties in 1868 which gave those of Wyoming the Wind River Reservation and those of Idaho the Fort Hall Reservation. Sedentarization of these buffalo-hunting nomads was completed during the 1870's, by which time the region was being settled by white ranchers and their Texas herds. Shortly after 1880, the buffalo herds had been almost completely exterminated, and so also had Plains Indian life.
The era from 1700 to 1880 was thus one of great change for the Shoshone. We recapitulate its principal periods.
1. The pre-horse period extended until approximately 1700.
2. The early equestrian period, from 1700 to 1750 was distinguished by the expansion of Shoshone-speaking peoples into the Canadian plains to the north and southward toward Texas, where they became known as Comanche.