Fort Laramie National Historic Site

Fort Laramie (/ˈlærəmi/; founded as Fort William and known for a while as Fort John) was a significant 19th-century trading post, diplomatic site, and military installation located at the confluence of the Laramie and the North Platte Rivers. They joined in the upper Platte River Valley in the eastern part of the present-day US state of Wyoming. The fort was founded as a private trading post in the 1830s to service the overland fur trade; in 1849, it was purchased by the United States Army. The site was located east of the long climb leading to the best and lowest crossing over the Rocky Mountains at South Pass and became a popular stop for migrants on the Oregon Trail. Along with Bent's Fort on the Arkansas River, the trading post and its supporting industries and businesses were the most significant economic hub of commerce in the region.

Fort William was founded by William Sublette and his partner Robert Campbell in 1834. In the spring of 1835, Sublette sold the fort to Thomas Fitzpatrick, a local fur trader. After a rendezvous in 1836, it was sold to the American Fur Company, which still had a virtual monopoly on the western fur trade. Starting as early as the fall of 1840, the American Fur Company began competing with the newly-established Fort Platte, built by Lancaster Lupton about a mile away from Fort William.

The American Fur Company hired workers from Santa Fe to construct an adobe fort to replace Fort William. This fort was named Fort John, after John Sarpy, a partner in the company. In 1849, the U.S. Army purchased the fort as a post to protect the many wagon trains of migrant travelers on the Oregon Trail, and the subsidiary northern emigrant trails which split off further west. These included the California and Mormon Trails. The middle reaches of the Mormon trail stayed on the north banks of the Platte and North Platte rivers, and merged with the other emigrant trails heading west over the continental divide from Fort Laramie. The name "Fort Laramie" gradually came into use, likely as a convenient shortening of "Fort John at the Laramie River".

The remaining structures are preserved as the Fort Laramie National Historic Site by the National Park Service.

In 1815 or 1816, Jacques La Ramee and a small group of fellow trappers settled in the area where Fort Laramie would later be located. He went out alone to trap in 1819 or 1820 and was never seen again. Arapahoe Indians were accused of killing La Ramee and burying his body in a beaver dam. The river was named "Laramie" in his honor, and later settlers used this name for the Laramie Mountains, the fort, and the towns of Laramie, Wyoming and Fort Laramie, Wyoming.

The original fort was constructed in the 1830s, probably in 1833–1834 by William Sublette and Robert Campbell. The overland fur trade was still prosperous when Jim Bridger and Tom Fitzpatrick bought the place.

The fort was located near the confluence of two rivers, so it commanded a broad plain with water on two sides; these formed a partial natural moat. In addition, the nearby confluence of the North Platte's waters had a ford easily used by travelers on what later became the northern overland emigrant trails following the North Platte River west from Nebraska. With the opening of the Mormon Trail on the north bank of the Platte and North Platte, the fort was a junction for westbound travelers. It was an anchor roughly a quarter of the way to either California or Oregon on the famous Oregon Trail. To the west, the common trail leaving Fort John-Laramie later spins off to the Mormon and California trails further west along the road to the Rogue River Valley. The main trail passed northwest to Oregon's Willamette Valley and Oregon City.

One of the early principal owner-trappers was William Sublette, and the fort was called Fort William before being sold to the American Fur Company in 1841. (John Jacob Astor, the founder, had left his company a decade before.) The name was changed to Fort John after John Sarpy, a partner in the company. The 1846 treaties established relatively stable western territories after viable routes west had become well published. By the time the westward migration along the Oregon Trail had markedly increased, the US Army had become tenants in the fort as well. The fort was located along the Laramie River just south of its mouth onto the North Platte River.