Established in 1853 and abandoned during the Utah War of 1857, the fort served to solidify Mormon influence and control in the area, as a base for local missionary efforts, and to supply food and other provisions for pioneers headed to Salt Lake City.

Several years later, Mormon pioneers (members of the Church of Jesus Christ of Latter-day Saints, or LDS Church) established Salt Lake City approximately 100 miles (160 km) to the south-west of Fort Bridger, and this new city became the principal settlement in the Utah Territory following the territory's establishment by the US Congress in 1850.

[1]: 9 An act passed by the Utah Territorial legislature gave themselves the right to control the operation of ferries on the Green River, near the Bridger Valley.

[1]: 14  At Fort Bridger the now illegal trade continued, and in August 1853, 150 men under the command of Sheriff James Ferguson were sent to stop it.

Afterwards they continued to the Green River, where they engaged the mountain men who had been unlawfully running ferries, killing some and seizing their livestock.

Church leadership in Salt Lake City called Orson Hyde to organize the effort to establish the “Green River Mission” and build a fort in the Bridger Valley.

[1]: 17  The goal of this mission would not only be to convert and “civilize” the local Shoshone, but to help maintain Mormon control in the area, and supply provisions to pioneers who still had a nearly 100-mile journey across the Wasatch Range to the Salt Lake Valley.

Many of the missionaries’ efforts were spent that first winter surviving off supplies from Salt Lake City and learning the Shoshoni language from Elijah B.

[1]: 46–47  In 1856, church leadership called 43 families from other settlements in the territory to join with the missionaries currently at Fort Supply and strengthen that community.

[1]: 28  By April 1856, the fort included a stockade that enclosed 10 acres (4.0 ha), 25 homes, and a two-story building used as a courthouse and for other public functions.

[1]: 51  At the time the fort was burnt, Jesse W. Crosby (present at the burning) indicated that 100 or more log houses, a sawmill, gristmill, and thrashing machine were located at the settlements.