History
The existence of trappers in the West in any numbers started with Manuel Lisa in 1807 [1]. A major influx of trappers was started by the expedition of Ashley's Hundred in 1822. This gave rise to yearly trapping expeditions with the trappers leaving St. Louis with supplies, returning with pelts which were used to pay off debts and traded for supplies, whiskey and other necessities.
In 1824 the rendezvous system began [2] which hauled supplies to the mountains in the spring and brought back pelts in the fall. Major W. H. Ashley started this system through the Rocky Mountain Fur Company. He sold this business to the outfit of Smith, Jackson and Sublette while still taking the profits by selling that firm their supplies. This system continued with other firms, particularly the American Fur Company, entering the field.
The beaver pelts had been needed to make the beaver hats then popular in England. Fashions changed in the early 1840s making beaver less valuable at a time that they were harder to find because of overtrapping. The opening of the Oregon Trail and the use of the Mormon Trail gave employment to the trappers who did not want to return to civil society.
2. Fred R. Gowans, Rocky Mountain Rendezvous (Layton, Utah: Gibbs M. Smith, 1985), 13.