The Oregon Trail is a 2,000-mile (3,200 km) historic east-west wagon route that connected various towns on the Missouri River to valleys in Oregon and locations in between. It was the oldest of the northern commercial and emigrant trails and was originally discovered and used by fur trappers and traders in the fur trade from about 1811 to 1840. In its earliest days much of the future Oregon Trail was not passable to wagons but was passable everywhere only to men walking or riding horses and leading mule trains. By 1836, when the first Oregon wagon trains were organized at Independence, Missouri, the trail had been improved so much that it was possible to take wagons to Fort Hall, Idaho. By 1843 a rough wagon trail had been cleared to The Dalles, Oregon, and by 1846 all the way around Mount Hood to the Willamette Valley in the state of Oregon. What became called the Oregon Trail was complete even as improved roads, "cutouts", ferries and bridges made the trip faster and safer almost every year.
After the American Revolutionary War various trails were found and used to connect the states of the east via the passes across the mountains (in Pennsylvania and Virginia) into the sparsely settled Northwest Territories, and as time went on, further west into the territories of Iowa and Missouri. The newly developed riverboats and steamboats traversing up and down the Ohio, Mississippi and Missouri Rivers helped speed settlement and development in the American mid-west--Ohio, Illinois, Indiana, Missouri, Iowa et al. These riverboats allowed passengers and supplies to be delivered to "jumping off points" for the Oregon Trail on the Missouri River cheaply, quickly and easily. West of the Missouri River, the next lands initially available for settlement with reportedly lush and fertile lands, forests, rivers and other possible sources of development, were along the far western Pacific coastal maritime lands in the Oregon Territory. From the early migration waves until the mid-1850s, most of the territories through which the Oregon Trail passed were still open lands uninhabited by white settlers.
This territory in the early 19th century was subject to competing claims by the United States and Britain, who had come to an arrangement by 1818 that is usually described as "joint occupancy". Britain's name for the region was the Columbia District and the sparsely settled territory was governed by the local regional department of the British Hudson's Bay Company. In about 1840 a change in men's fashion that avoided using the felt from beaver pelts to make men's hats essentially ruined nearly all the fur trade in North America. After 1843, when 700-1000 U.S. settlers went to Oregon, Britain became much more amenable to a boundary compromise. The Oregon Treaty of 1846 settled the major boundary disputes with Britain and the U.S., opening the territory to undisputed settlement.
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. Different travelers started on the trail from several diverse (and changing) "jumping off points" in Missouri and later from locations in the Iowa and Nebraska Territories. The various branches of the eastern Oregon trail(s) merged somewhere along the lower Platte River Valley, near Fort Kearny, Nebraska Territory. Initially the Missouri river ports of Kansas City, Kansas/Independence and St. Joseph, Missouri were the main Oregon Trail heads. Small steamboats carrying fur traders navigated the Missouri River up to the Yellowstone River as early as 1832. Larger steamboats traveling much above St. Joseph were blocked until dredging opened a bigger channel in 1852. After 1846 many Oregon travelers started nearer the confluence of the Platte and Missouri Rivers from Kanesville, Iowa (est. 1846 and renamed Council Bluffs, Iowa in 1852) and Omaha, Nebraska (est. 1852). By 1847 the Mormons, who had temporarily settled in large numbers in Iowa and Nebraska Territory on the Missouri River after being driven out of Nauvoo, Illinois, had established three ferries across the Missouri River near Kanesville, and others built even more ferries.
Oregon Trail travelers with problems could usually get repairs, new supplies, fresh teams and help from fort-trading posts such as the U.S. Army, which ran Fort Kearny and Fort Laramie. Jim Bridger's Fort Bridger and Hudson 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 rapidly diminished as the railroad was able to fulfill most travel needs, provided transcontinental travelers could afford the tickets (about $69.00, and seven days travel in economy class). 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 emigrant trail's legacy persisted well into the middle of the 20th century, however, for many local railroads and automobile roads were built over or near most of the trails as local travelers continued to travel to cities originally established along the Oregon Trail and its network of connected routes.
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.
The four- to six-month journey spanned over half the continent as the wagon trail or one its variants led about 2,000 miles (3,200 km) west through territories and land that later became seven states: Iowa, Missouri, Kansas, Nebraska, Wyoming, Idaho, and Oregon. Extensions of the Oregon Trail were the main arteries that fed settlers into six more states: Colorado, Utah, Nevada, California, Washington, and Montana.