In 1850 Bridger consulted and guided the Stansbury expedition, which established a road much of which would later become the route of the Overland Stage and the Union Pacific Railroad. The same year, the territory of Utah was created; it included under its jurisdiction the Fort Bridger area.
Animosity between Bridger and the Mormons festered in the summer of 1853. Mormon leaders were convinced that Bridger was engaged in illicit trade with the Indians, especially guns and ammunition, and that he had stirred hostility among the Native Americans against the Mormons. Mormon leaders revoked Bridger's license to trade and issued a warrant for his arrest; however, before the posse's arrival Bridger had fled.
By the end of 1853, the Mormons had begun to move in and secure control of Bridger's Green River Basin, opting to establish Fort Supply rather than occupy Fort Bridger. Bridger had gone to the east, but returned to the mountains in 1855. That summer, Bridger sold his fort to the Mormons for $8,000. The Mormons paid Bridger $4,000 in gold coin that August; however, the final payment was not made until 1858, when Vasquez received the remaining $4,000 in Salt Lake City.