Bear river was discovered September 9, 1812, by Robert Stuart's fur trade party on their way from Snake river in search of South Pass. They called it Miller's river for Joseph Miller, a member of their party who thought he had hunted farther up stream the preceding fall. But as they proceeded from Fish creek to the bend of Bear river at Sheep rock, Soda Springs, and finally past Bear lake outlet to Thomas' fork, Miller never did find his hunting ground. He had been nearby on the upper Blackfoot, not Bear river, and had confused the two adjacent valleys. Stuart's party did not stop to trap; facing a long, hard trip from Astoria to St. Louis, Stuart hastened on. He saw Bear lake outlet, but if he or his men noticed the lake, he did not mention it. Finally in 1818, Donald MacKenzie brought a North West Company fur hunters' brigade to Bear lake. Michel Bourdon, a French Canadian trapper with MacKenzie, descended Bear river through Gentile valley to discover Cache valley. There he trapped on blacksmith's fork, then known as Bourdon's river. MacKenzie spent a few weeks at Bear lake in the summer of 1819, and Michel Bourdon or Finnan MacDonald may have returned with Hudson's Bay Company expeditions in 1822 or 1823; they headed that way but left no record of where they went.
After William H. Ashley sent out a large group of mountain men from St. Louis to join the Rocky Mountain fur trade, one of his parties crossed South Pass in the summer of 1824 and reached Bear lake that fall. John H. Weber led this group, which went on in the fall of 1824 to settle down for the winter on Cub river in Cache valley. This campsite, located just north of what then was the Mexican boundary, now is in Idaho close to the town of Franklin. From this camp Jim Bridger set out to explore lower Bear river, which he followed to Salt Lake. Ephriam Logan also went from Weber's camp into later Utah, where he trapped on Logan river. From 1824-1828 Cache valley and Bear lake served as a major base for the Rocky Mountain fur trade, and in the spring of 1825, Peter Skeene Ogden brought the Hudson's Bay Company's annual Snake expedition through Cache valley to Ogden's Hole (directly south of Cache valley) and back again. Zacharias Ham brought still another party from the east to Bear river that spring.
After meeting with Ashley in a trappers' rendezvous on Green river, many of the mountain men returned to Cache valley to spend another winter. Early in 1826, several parties radiated out from Cache valley for spring hunts: William Sublette and David E. Jackson took an expedition all the way to Payette lake, and John Weber, Jim Bridger, and another group went north to the Portneuf. They all returned for the 1826 rendezvous which was held in Cache valley. There, on July 18, 1826, William H. Ashley sold out his fur trade business to a new firm of Jedediah Smith, David E. Jackson, and William H. Sublette. Ashley agreed to bring supplies to the next rendezvous at Bear lake. Jedediah Smith then set out for California while the other partners trapped in the Snake and Yellowstone country. Except for Smith's men, they generally returned late in 1826 for another winter in Cache valley. William L. Sublette went out to St. Louis that winter, though, where he got his company a license to trade in Cache valley and other western places.
When he came to Bear lake with supplies for the trappers' rendezvous, June 13, Ashley brought along a small wheeled cannon for protection along the way. In doing so, he proved that the route of the later Oregon trail was suitable for wagons as far as Bear river valley, anyway. He almost needed his cannon at Bear lake. A band of 120 Blackfeet got into a fight with the Shoshoni at Bear lake, and six of the mountain men joined the battle, helping the Shoshoni against the Blackfeet. Samuel Tulloch came out with a withered hand from a severe wrist injury, and there were six Shoshoni casualties, three of them fatalities. Peace with the Blackfeet was too much to expect, but the mountain men did arrange for peace between the Shoshoni and Utes. Both groups were given "presents of guns, balls, knives, &c.," in addition to the help that William Sublette and his companions offered during the battle with the Blackfeet. Although Jedediah Smith, when he returned from California, July 3, could bring back none of his beaver catch, the upper Snake expedition had fared well. Altogether, 7400 pounds of fur, valued at $22,690 were traded, and the new form of Smith, Jackson, and Sublette was able to pay off their debt to Ashley. When rendezvous broke up, July 13, Jedediah Smith set out for California where he had left his men, while David E. Jackson and William L. Sublette went back to St. Louis with Ashley. Robert Campbell led an expedition of trappers back to the upper Snake, planning to return for another winter in Cache valley. That did not work out. Extremely deep snow that winter stopped Campbell on the Portneuf, and the other mountain men who planned to return to Cache valley from the south had to spend the winter at Salt Lake. From then on, Cache valley lost its early popularity as a winter quarters.
Rendezvous at Bear lake in 1828 brought the mountain men of the Rockies back for another summer celebration and trade fair. Even Joshua Pilcher's remote American Fur Company party headed for Bear lake in 1828. A Blackfoot band showed up again, in time to attack Robert Campbell's party at the north end of the lake. Again the Indians were driven off after a sharp four hour fight. Campbell lost his cook and some horses, but was able to obtain help from the rendezvous at the south end of the lake. After this second Bear lake rendezvous, fur hunting generally shifted mostly to other areas. Ogden brought his Hudson's Bay Company Snake expedition back to Bear river, where he camped near Grace, February 7-23, 1829, without seeing any beaver. He had no better luck in Cache valley. An 1831 rendezvous (one of two or three for that year, because of failure of the supply train to arrive on time) assembled in Cache valley. But systematic trapping of the Snake country had depleted the fur resources of the northwest, and several years of steady pressure had cut down the trade along Bear river also.
Soda Springs, at the northern bend of Bear river, continued to be a popular attraction for trappers coming through that part of the country, and received a lot of publicity in Washington Irving's Adventures of Captain Bonneville. Even as late as 1840, Osborne Russell found a number of French Canadian and metis trappers camped with the Cache valley Shoshoni. By that time, Fort Hall (to the northwest on Snake river) served as the fur trade outlet for the whole region. Trappers who had learned the country during the fur trade began after 1840 to serve as emigrant guides, and in 1841 the California bound Bidwell-Bartleston party came down Bear river past Soda Springs and then continued southwest through Cache Valley as they sought a route to the Humboldt. For a time, particularly during the California gold rush, Thomas L. Smith ran a post to accommodate emigrants on Bear river not far from Bear lake. By then, Mormon settlement had reached Salt Lake, and by 1856, Mormon colonization extended to Cache valley. Fort Hall closed that same year, and fur hunting had long since gone into a hopeless decline.