Now located in Wyoming, Fort Bridger from 1850 to 1858 was in Utah Territory. The location was in doubt after the Utah War of 1857-58. The northeast corner of the territory was gradually taken by Wyoming territorial officials, both army and civilian, and officially annexed when Wyoming became a state in 1868.

Fort Bridger was built in 1842-43 by mountain men Jim Bridger and Louis Vasquez. The spot chosen was at Blacks Fork, west of Ham's Fork of the Green River. The fort became a resupply station for early western pioneers. Wagon repairs, food supplies, animal replacements, trail directions, liquor, and ammunition were available for a price. The fort ownership remained unchallenged until the arrival in 1847 of the Mormon pioneers, who settled 104 miles southwest of the fort in the Salt Lake Valley.

The Utah legislature created Green River County in the northeast corner of the territory in 1850. By 1852 the lifestyles of the rough mountain men and the Indians near the fort began to conflict with the Utah pioneers.

Federal Indian agents as early as 1849 accurately predicted a coming conflict, which came about over money as well as control of the Green River ferries, the courts, criminal prosecution, taxes, land registration, water rights, and the fort itself.

Reports of liquor and ammunition being sold to the Indians near the fort reached Brigham Young as early as 1848. This practice was in violation of federal law, and Brigham Young as federal Indian agent was determined to stop the practice. On 26 August 1853 a Utah territorial (Mormon) militia of forty-eight men led by William H. Kimball started for Fort Bridger from Salt Lake City. Jim Bridger was warned and escaped minutes before the Mormons arrived. The Mormon men discovered ample liquor which they "destroyed in small doses," but found no ammunition.

In October, fifty-three men under Isaac Bullock left Salt Lake for Fort Bridger to back up the first assault. They built Fort Supply as a Mormon supply station twelve miles to the southwest. Fort Bridger, located at 7,000 feet elevation, experiences severe winters. With the approach of winter, the Mormon men, except for a few left to guard Fort Bridger, retreated back to Salt Lake or to Fort Supply until the coming of warmer weather.

Bridger wrote a letter to General B.F. Butler, a U.S. Senator, in October 1853 claiming he was "robbed and threatened with death by the Mormons" and that over $100,000 of his goods and supplies had been stolen.

The following spring (1854), Brigham Young made plans to take control of Fort Bridger by sending in fifteen well-armed men for reinforcement. They also were to take control of the Green River ferries. Both the fort and the ferries became an integral part of the Mormon settlement plan. These men built a stone wall around the fort, vestiges of which remain to this day.

This condition prevailed until late July 1855 when Bridger returned to the fort. The Mormons asked him to sell but he at first refused when he noticed the improvements. He finally agreed to the sale after being persuaded by William Hickman, a member of the Mormon militia, and Almirin Grow. An agreement was reached on 3 August 1855 with a purchase price of $8,000--$4,000 downpayment and the balance due 3 November 1856, fifteen months later.

The fort again became a point of contention in the fall of 1857 when the U.S. Army, under the command of General Albert Sidney Johnston, marched across the high plains, determined to use the fort as a base to enter Utah Territory and quell the reported seditious activities of the Mormons. However, on the night of 7 October 1857 the fort was burned by William A. Hickman and his brother. Johnston's Army, with little shelter in a severe winter, without adequate food and clothing and surrounded by freezing, dying animals, endured untold suffering as they camped in the open until the spring thaw.

Brigham Young paid the remaining $4,000 owed on the fort during the peace negotiations to end the war and thought he owned it. However, Congress rejected Brigham Young's claim to the fort after the war. Jim Bridger continued to press his claim for payment on a lease he had signed with the army. Bridger died in July 1881 with Congress still unresponsive to his claim. After years of effort by his descendants, Congress appropriated $6,000 in 1899 to settle the matter.

William Alexander Carter came with Johnston's Army as a sutler or storekeeper in 1858. He stayed on with his family rebuilding and restocking the fort, and he eventually became wealthy. A highly respected man, he was soon known as "Mr. Fort Bridger," Wyoming's first millionaire.

The Union Pacific tracks laid in 1869 bypassed the fort by nine miles, reducing it to the historical landmark it is today. Carter's family continued to live at the fort until 1928, when it was sold to the Wyoming Historical Landmark Commission for preservation. As a Wyoming state park it remains a permanent reminder of the early years of western settlement.