Fort Bridger was originally a 19th-century fur trading outpost established in 1842, on Blacks Fork of the Green River, in what is now Uinta County, Wyoming, United States and was then part of Mexico. It became a vital resupply point for wagon trains on the Oregon, California, and Mormon Trails. The US Army established a military post here in 1858 during the Utah War, until it was finally closed in 1890. A small town, Fort Bridger, Wyoming, remains near the fort and takes its name from it.
The Mormon Trail is the 1,300-mile (2,100 km) route from Illinois to Utah on which Mormon pioneers (members of the Church of Jesus Christ of Latter-day Saints) traveled from 1846 to 1869. The Mormon Trail is a part of the United States National Trails System, known as the Mormon Pioneer National Historic Trail.
The Mormon Trail extends from Nauvoo, Illinois, which was the principal settlement of the Latter Day Saints from 1839 to 1846, to Salt Lake City, Utah, which was settled by Brigham Young and his followers beginning in 1847. From Council Bluffs, Iowa to Fort Bridger in Wyoming, the trail follows much the same route as the Oregon Trail and the California Trail; these trails are collectively known as the Emigrant Trail.