Mackenzie attempted to set up a post on the Boise River. William Ashley organized the Rocky Mountain Fur Company, which instituted the practice of annual rendezvous. Captain B.L.E. Bonneville took a wagon train across South Pass to Green River. Forts Laramie, Boise, and Hall were established. Henry H. Spalding established a mission near Lapwai, where he prints the Northwest's first book, establishes Idaho's first school, develops Idaho's first irrigation system and grows the state's first potatoes.
Heavy traffic continues on the trail for many years.
U.S. Military post, Cantonment Loring, established near Fort Hall. French Canadians discover gold on the Pend Oreille River. Washington Territory created. Abandoned in 1858. Franklin, first town in Idaho, established.