The outfit lost their horses, which had been traveling overland with a party under General Ashley’s command, to the Assiniboines, however, and as Ashley returned to St. Louis, the balance of the command “forted up” at the mouth of the Yellowstone that fall. This was “Fort Union.” Thus Jim became a “Hivernant.” He wintered in the mountains and was a greenhorn no longer, when spring came he was a Mountain Man.

With the breakup of the ice that spring, Major Henry promptly started on the spring hunt, intending to combine trapping with trading with the Indians. The party was jumped by Blackfeet at or near the Great Falls of the Missouri, and the Indians drove them into retreat. They made their way back to the fort, losing four men killed, and with several wounded. Bridger had his first taste of Injun fightin’. It was not a palatable one.

In the meantime Ashley had not arrived at the fort, but some time after the return of Henry’s party Jedediah Smith (also recruited by Ashley in the spring of 1822) arrived with one companion and the most unwelcome news that the General’s party had run into difficulty with the Arikaras, and was in dire need of reinforcements. Henry, with about 80 of his men, including Bridger, returned with Smith to aid Ashley, arriving in time to achieve a doubtful and shortlived truce with the Indians, with the help of Colonel Leavenworth and a force of soldiers, trappers, and friendly Sioux, who had moved up from Fort Atkinson.

Major Henry and his men, having received their supplies from Ashley, set out at once for the fort on the Yellowstone, intending to again proceed from there into the wilderness in search of furs. Shortly after the Arikara fight occurred an incident that was to have a pronounced and lasting influence on young Jim. The aforementioned Hugh Glass was a hunter for the party, an elderly, tough Pennsylvanian. On the occasion which led to his claim to fame as a victim of one of the most tragic “bear stories” ever related, he was ahead of the party on a hunt, when he was attacked and mauled by a she-grizzly. So severely was the old man mangled that his companions despaired of his life. Here was a knotty problem. He could not be moved, he could not be left alone. Yet the party wanted to get out of the hostile Indian country and go about the business of collecting furs as speedily as possible. Major Henry decided that two men must remain with old Hugh until he died. No one wanted to stay, but the Major proposed that every man contribute a dollar as an inducement to those left behind with the old man. The men were more than willing to subscribe to the arrangement, Jim volunteered to stay, and another, Fitzgerald by name, reluctantly consented to remain also. So it was determined, and the Major and the rest of the party moved on.

Old Hugh clung tenaciously to life, while Jim and Fitzgerald sat and fretted, constantly in fear of discovery and attack by the hostile Arikaras. Fitzgerald found Indian sign on the third day. As far as he was concerned that clinched it, they couldn’t do the old man any good, he was certain to “go under” anyway, in the meantime they were in terrible danger. He finally persuaded Jim to leave the dying oldster, taking with them Glass’ rifle, powder, knife, all his “fixins,” because it wouldn’t be reasonable to show up without them, they wouldn’t leave the things with a dead man, and their story to the Major would have to be that Glass had died. The old fellow was barely conscious, and they slipped away, catching up to the rest of the party just before it reached the fort on the Yellowstone.

Jim was worried, memories of the old man haunted him, suppose he hadn’t died! Imagine his dismay when a few weeks later Glass appeared in the trappers’ camp. Jim expected death at the hands of the hunter, he probably felt that he deserved it, but Glass seemed to be most interested in the whereabouts of Fitzgerald, placing the blame on him.

Glass had an incredible story to tell. Realizing that he had been deserted, he determined to save himself, and crawling, hobbling, barely able to move at all, he started for Fort Kiowa, nearly 100 miles away. He made it, and as soon as possible thereafter he started upriver again to locate Henry’s party. He wanted “Fitz.” When he learned that Fitzgerald had left the Major and gone downriver to Fort Atkinson, Glass went after him, with the avowed intention of revenge. He found him, but found also that he had joined the Army. The commanding officer at Fort Atkinson heard his story, persuaded him that shooting a soldier would be a serious matter, compelled Fitzgerald to make good the old man’s losses, and thus the matter was ended, perhaps not to the complete satisfaction of the justly irate old hunter, but at least without bloodshed. Jim never forgot. The rest of his life the lesson remained with him, and his record of service to others, devotion to duty rather than self-interest, is sufficient evidence that the lesson was well learned.

Bridger’s exploits in the years that followed were legion. In 1824 he explored the Bear River, discovering the Great Salt Lake which at that time he believed to be an arm of the Pacific. He advanced from a trapper in the employ of others to a partnership in the Rocky Mountain Fur Company with Fitzpatrick, Milton Sublette, Fraeb and Gervais, when in 1830 they brought out the company of Jedediah Smith, David Jackson, and Bill Sublette. He is best known for his services as a guide. As his knowledge of the Rockies increased with his years of wandering over the west, he repeatedly served as a scout for the Army, in which capacity he was invaluable, his knowledge of Indians and their ways was second to none. He guided many notable expeditions, one of them the Raynolds party, into Jackson Hole. It was said of him that he could brush clear a patch of earth and inscribe thereon, with a twig, an accurate and detailed map of any section of the Northern Rockies, depending only upon a photographic memory of the terrain.

Bridger visited Jackson Hole for the first time in 1825, with Thomas Fitzpatrick and 30 trappers, following Jedediah Smith’s route of the previous year, that is by way of the Hoback River from the south. They passed through the Hole, going north along the Snake River into the Yellowstone. This was probably the first trapping venture with Jackson Hole as the center of operations. Mattes says, in Jackson Hole, Crossroads of the Fur Trade, 1807-1840:

This was a notable occasion, for the full glory of the Tetons was then revealed for the first time to these two young fur trappers who were destined in later years to become famous as guides for the government explorers and the emigrant trains, and as scouts for the Indian-fighting armies.