After 1840 steam-powered riverboats and steamboats traversing up and down the Ohio, Mississippi and Missouri rivers sped settlement and development in the flat region from the Appalachian mountains to the American Rocky Mountains. The boats serviced the jumping off points for wagon trains that crossed the mountains headed to rich farmlands in Oregon and California. With disputes with Spain and Britain settled by 1848, the new lands proved highly attractive. Getting there by sea meant either a very long trip around South America or through Panama-both were expensive and dangerous and took longer than walking.
The eastern part of the Oregon Trail spanned part of the future state of Kansas and nearly all of what are now the states of Nebraska and Wyoming. The western half of the trail spanned most of the future states of Idaho and Oregon. From various "jumping off points" in Missouri, Iowa or Nebraska, the routes converged along the lower Platte River Valley, near Fort Kearny, Nebraska Territory. Small steamboats carrying fur traders navigated the Missouri River up to the Yellowstone River in Montana as early as 1832. Larger steamboats traveling much above St. Joseph were blocked until dredging opened a bigger channel in 1852.
Oregon Trail travelers could purchase repairs, new supplies, fresh teams and help from fort-trading posts such as Fort Kearny and Fort Laramie. Jim Bridger's Fort Bridger and Hudson's Bay Company owned: Fort Hall and Fort Boise in Idaho; Fort Nez Perces (Fort Walla Walla) in Oregon and Fort Vancouver in Washington. Other supplies, fresh teams and repairs could often be obtained from temporary trading posts and ferries set up by entrepreneurs along the trail during the traveling season. From the early to mid 1830s, but especially after the organization of the first large wagon trains in Independence, Missouri in 1841 and through the epoch years 1846 � 1869 the Oregon Trail and its many off shoots was used by about 400,000 settlers, ranchers, farmers, miners, and businessmen and their families. The eastern half of the trail was also used by travelers on the California Trail (from 1843), Bozeman Trail (from 1863), and Mormon Trail (from 1847) which used many of the same eastern trails before turning off to their separate destinations.
Once the first transcontinental railroad by the Union Pacific and the Central Pacific was completed in 1869, the use of this trail by long distance travelers fell off because the train took seven days and at $69 was much cheaper. Travelers going to Oregon could take the train to California and catch a coastal steamer to Oregon. By 1883 the Northern Pacific Railroad had reached Portland, Oregon, and thereafter there were less and less wagon trains each year along the western trail. The legacy persisted as highways such as Interstate 80 followed the same course westward and passed through towns originally established to service the Oregon Trail.
To complete the journey in one traveling season most travelers left in April to May-as soon as there was enough grass for forage for the animals and the trails dried out. To meet the constant need for water, grass, and fuel for campfires the trail followed various rivers and streams across the continent. The network of trails required little initial preparation to be made passable for wagons. People using the trail traveled in wagons, pack trains, on horseback, on foot, and sometimes by raft or boat to establish new farms, lives, and businesses in the Oregon Country.