The first missionary group to the West left Independence in 1834. Led by Jason Lee, its members joined a party headed by New England merchant Nathaniel Wyeth. They largely followed the Platte River. At the Snake River, Wyeth built a post, Fort Hall, in Idaho (near present-day Pocatello), which was later bought by the Hudson’s Bay Company; it subsequently became a major supply outpost for future emigrants. The Wyeth-Lee party was the first group to travel the entire course of what was to become the Oregon Trail.

Perhaps the most significant of the pioneers to the Northwest was Marcus Whitman, a physician who had become a Congregational missionary. In the mid-1830s he and fellow missionary Henry Harmon Spalding established missions in the Oregon country—Whitman among the Cayuse Indians at Waiilatpu (near present-day Walla Walla, Washington) and Spalding among the Nez Percé at Lapwai (near present-day Lewiston, Idaho). In addition, Narcissa Whitman and Eliza Spalding, the wives of the two men, accompanied them on their journey, thus becoming the first white women to cross the South Pass and the Continental Divide.

By then, interest in the East for the Oregon country had begun to grow. In 1840 Robert Newell and Joseph Meek, leading a small party out from Fort Hall and guided by mountain man Thomas Fitzpatrick, became the first emigrants to reach the Willamette valley by land. The following year several dozen pioneers led by John Bartleson and John Bidwell were the first emigrants credited with using the nascent Oregon Trail to migrate to California by wagon train (at Fort Hall, half of the group headed instead for Oregon).

In the winter of 1842–43 Whitman made a remarkable 3,000-mile (4,800-km) journey back east on horseback to persuade his sponsors to continue supporting the missions. He also conferred with federal officials in Washington, D.C., about settlement in Oregon, and those discussions became a major factor in convincing Easterners to move to the lands beyond the Rocky Mountains. Perhaps the final inspiration was supplied by the glowing reports of the region from mapmaker and explorer John C. Frémont, who famously explored the West with guides Kit Carson and Thomas Fitzpatrick in the mid-1840s and did much to dispel the myth of the Great American Desert.

In 1842 missionary Elijah White—also a great proponent of westward migration—had organized and helped lead the second sizable wagon train on the Oregon Trail. That group was the first on the trail to include more than 100 pioneers. Whitman began his return West the following spring, joining up with a remarkable caravan of nearly 1,000 settlers—known in Oregon history as the “great migration”—the first of many large-scale groups of emigrants who now began to pour into the Oregon country.

The mission at Waiilatpu became an important stopping point for the increasing numbers of emigrants to Oregon. In 1847, however, Whitman, his family, and several other whites were massacred by Indians following the outbreak of an epidemic of measles. The incident helped spur passage of a bill establishing the Oregon Territory (1848) and contributed to the Cayuse War between Indians and settlers, which did not end until 1850.

Mormon emigrants were also pioneering users of the Oregon Trail. After their leader Joseph Smith was murdered in Nauvoo, Illinois, in 1844, church members decided to move their community to the Great Salt Lake region. The initial group of what would be thousands of Mormon settlers departed in 1846, crossing Iowa before establishing winter quarters in what would become Omaha, Nebraska. From there this first wave followed essentially the same route as the Oregon Trail before breaking off to the south just west of the Continental Divide and heading toward Utah.

Varied routes

A common misconception is that the Oregon Trail was a single track that never changed. In reality, the trail was more like a braided band, frayed at the ends, which meandered a little with each year and with changing weather conditions. While in certain locations the trail did converge into a single passage, in other places the wagon trains might spread out, making the trail up to 0.5 mile (0.8 km) wide or more. In places there might have been many parallel routes, sometimes a few miles away from each other.

Initially, Independence, Missouri, was the departure point for the Oregon Trail because it was also the eastern terminus of the older Santa Fe Trail. Most of the early emigrants arrived at Independence after having loaded their wagons and belongings directly onto steamboats traveling up the Missouri River from St. Louis. They disembarked where the river turns sharply north—roughly at Independence—and began the long overland journey. Enterprising individuals quickly recognized that outfitting the overlanders was highly profitable. Soon suppliers had set up shop in St. Joseph, which was farther north and west in Missouri than Independence. Those starting there eliminated some 20 miles (30 km) and several river crossings from the first leg of the trek.

Within a few years, wagon trains were departing from several towns along the Missouri River between St. Joseph and Council Bluffs, Iowa (then called Kanesville). The more northerly jumping-off spots appealed to those coming from places such as Illinois and Indiana; the travelers could outfit themselves in the towns where they lived, buying their supplies and equipment from people they knew rather than from traders who were apt to gouge the greenhorns. Emigrants who left from any place south of Council Bluffs eventually followed the south bank of the Platte River until they crossed it in western Nebraska. Those who departed from Council Bluffs—by 1850 they were in the majority—stayed on the north bank of the Platte. The two trails joined in Wyoming at either Fort Laramie or near present-day Casper.

The Oregon Trail and the California Trail traced the same route until they split, either at Fort Bridger in southwestern Wyoming or at Soda Springs or the Raft River in southeastern or southern Idaho, respectively. Those heading to Oregon continued northwest, while those traveling to California went southwestward through the deserts of northern Utah and Nevada before crossing the Sierra Nevada range and descending into the Sacramento area of California and beyond. The California branch was especially popular in the late 1840s and early ’50s, as hordes of gold seekers joined the gold rush to California.