In 1863 gold and silver were discovered at Alder Gulch in what is now southwestern Montana. In 1864 prospectors, miners, and adventurers flocked to the Montana Territory. A fast and safe route was needed to get to the new gold fields. So, mountain man Jim Bridger blazed a trail west of the Bighorn Mountains that was safer than the Bozeman Trail through Sioux country in the Powder River Basin. Bridger's trail was much shorter than the Oregon Trail and Lander Cutoff, or longer routes by way of Fort Bridger or Salt Lake City.

Bridger's route was no accident. Plains Indian societies were increasingly encroached upon due to United States Manifest Destiny, followed by gold discoveries, and settlement in the West. The primary reason Bridger blazed his trail was to avoid the hostilities of the Lakota Sioux and their allies, the Northern Cheyenne and Northern Arapaho. They wanted for themselves the rich hunting grounds of the Powder River Basin assigned to them in 1851 as an integral part of the Fort Laramie Treaty. During the mid-1860s, the Sioux carried out "Red Cloud's War", a campaign to force Euro-Americans and the U.S. Army from the Powder River country. Their efforts resulted in the closure of the Bozeman Trail and abandonment of the forts as part of the Fort Laramie Treaty of 1868.

The Bridger Trail route to the gold fields of Montana did not gain military support and lasted only one season as an emigrant route. It was important nevertheless because it funneled a large number of emigrants (approximately 25 percent of the 1864 population of Virginia City) into Montana during a single trail season. Many of the emigrants homesteaded, rose to prominence in their communities, and made important contributions to territorial development and much more. Of course, the trail is also historically significant for its association with Jim Bridger who was notable for his contributions to the development of the American West as one of the most renowned explorers and guides in American history.

Three decades later in the 1880s and 1890s, the main Bridger Trail route served as the trunk line for a freighting network of wagon roads that connected remote ranches in the Lost Cabin area with Casper to the east and the Bighorn Basin to the north. The route also provided rural communities in the Bighorn Basin access to markets via the railhead in Billings, Montana. This was important for sustaining the emerging economies of those towns into the twentieth century. The Chicago, Burlington and Quincy Railroad was built into the Bighorn Basin by 1901, but freight wagons continued to transport a variety of merchandise to and from the railheads along portions of the old Bridger Trail prior to the advent of motorized transportation.

Bridger's trail served two historic roles. It was a safer route for emigration to Montana during a period of Native American resistance to Euro-American encroachment, and it was the genesis of a late nineteenth and early twentieth century transportation route that fostered early settlement in a region without a system of roads.