The U.S. Army's Role in Protecting the Oregon Trail in Wyoming 1842 to 1870
Lieutenant John C. Fremont led an expedition west in 1842 to map a route to Oregon Territory. The scout, Kit Carson, guided the expedition. Lieutenant Fremont's report and Charles Preuss's maps were used by many emigrants.
In June of 1849, the First Army post in Wyoming was established at Fort Laramie, also known as Fort John. Fort John was an old American Fur Company trading post located near the confluence of the Laramie and North Platte Rivers. The mission of Army units stationed at Fort Laramie was to protect emigrants travelling the Oregon Trail.
East of Fort Laramie at the confluence of Horse Creek and the North Platte River, the first Fort Laramie Treaty (1851) was signed by representatives of the Sioux, Cheyenne, Arapaho, Gros Ventre, Mandan, Assiniboin, and Crow Nations to allow whites safe passage along the Oregon Trail.
On August 19, 1854, an emigrant's lame cow was killed and eaten by members and guests of a Brule-Sioux village located approximately nine miles east of Fort Laramie. This led to an event known as the "Grattan Massacre". Lieutenant John Grattan's badly mishandled attempt to arrest High Forehead, a Miniconjou-Sioux, who had killed the cow, resulted in the deaths of Grattan, 29 soldiers, and Brule Chief Conquering Bear.
Near present-day Casper, Wyoming, the Army established Camp Payne in 1858 and abandoned it in 1859. In 1862, Platte Bridge Station was established nearby. Two separate battles would occur near the station on July 26, 1865 involving Cheyenne, Sioux, and Arapaho warriors and the US Army. In the first, Lieutenant Caspar W. Collins and four troopers were killed. Sergeant Amos J. Custard and twenty-two troopers were killed in the final battle. Sixty warriors involved in the battles were estimated to have been killed. Platte Bridge Station was renamed Fort Casper in honor of young Lieutenant Collins.
With the completion of the Continental Railroad in 1869, and the relocation of the telegraph line, the use of the Oregon Trail dramatically decreased and so did the Army's role in protecting the trail.