The beginnings of the California and Oregon Trails were laid out by mountain men and fur traders from about 1811 to 1840 and were only passable initially on foot or by horseback.
South Pass, the easiest pass over the U.S. continental divide of the Pacific Ocean and Atlantic Ocean drainages, was discovered by Robert Stuart and his party of seven in 1812 while he was taking a message from the west to the east back to John Jacob Astor about the need for a new ship to supply Fort Astoria on the Columbia River—their supply ship Tonquin had blown up.
In 1824, fur traders/trappers Jedediah Smith and Thomas Fitzpatrick rediscovered the South Pass as well as the Sweetwater, North Platte and Platte River valleys connecting to the Missouri River.

British fur traders primarily used the Columbia River and Snake Rivers to take their supplies to their trading posts.
After 1824 U.S. fur traders had discovered and developed first pack and then wagon trails along the Platte, North Platte, Sweetwater and Big Sandy River (Wyoming) to the Green River (Colorado River) where they often held their annual Rocky Mountain Rendezvous (1827–40) held by a fur trading company at which U.S. trappers, mountain men and Indians sold and traded their furs and hides and replenished their supplies they had used up in the previous year.

A rendezvous typically only lasted a few weeks and was known to be a lively, joyous place, where nearly all were allowed—free trappers, Native Americans, native trapper wives and children, travelers, and later on, even tourists who would venture from even as far as Europe to observe the games and festivities.
Trapper Jim Beckwourth describes: "Mirth, songs, dancing, shouting, trading, running, jumping, singing, racing, target-shooting, yarns, frolic, with all sorts of drinking and gambling extravagances that white men or Indians could invent."
Initially from about 1825 to 1834 the fur traders used pack trains to carry their supplies in and the traded furs out.
The beginnings of the California and Oregon Trails were laid out by mountain men and fur traders from about 1811 to 1840 and were only passable initially on foot or by horseback. South Pass, the easiest pass over the U.S. continental divide of the Pacific Ocean and Atlantic Ocean drainages, was discovered by Robert Stuart and his party of seven in 1812 while he was taking a message from the west to the east back to John Jacob Astor about the need for a new ship to supply Fort Astoria on the Columbia River—their supply ship Tonquin had blown up. In 1824, fur traders/trappers Jedediah Smith and Thomas Fitzpatrick rediscovered the South Pass as well as the Sweetwater, North Platte and Platte River valleys connecting to the Missouri River.
British fur traders primarily used the Columbia River and Snake Rivers to take their supplies to their trading posts. After 1824 U.S. fur traders had discovered and developed first pack and then wagon trails along the Platte, North Platte, Sweetwater and Big Sandy River (Wyoming) to the Green River (Colorado River) where they often held their annual Rocky Mountain Rendezvous (1827–40) held by a fur trading company at which U.S. trappers, mountain men and Indians sold and traded their furs and hides and replenished their supplies they had used up in the previous year.
A rendezvous typically only lasted a few weeks and was known to be a lively, joyous place, where nearly all were allowed—free trappers, Native Americans, native trapper wives and children, travelers, and later on, even tourists who would venture from even as far as Europe to observe the games and festivities. Trapper Jim Beckwourth describes: "Mirth, songs, dancing, shouting, trading, running, jumping, singing, racing, target-shooting, yarns, frolic, with all sorts of drinking and gambling extravagances that white men or Indians could invent." Initially from about 1825 to 1834 the fur traders used pack trains to carry their supplies in and the traded furs out.
California Trail