The Oregon Trail was one of the main overland migration routes on the North American continent, leading from locations on the Missouri River to the Oregon Country.

Between 1841 and 1869 the Oregon Trail was used by settlers, ranchers, farmers, miners, and businessmen migrating to the Pacific Northwest. The eastern half of the trail was also used by travelers on the California Trail, Bozeman Trail, and Mormon Trail which used much of the same trail before turning off to their separate destinations. Once the first transcontinental railroad (First Transcontinental Railroad) by the Union Pacific and the Central Pacific (Central Pacific Railroad) 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. By 1883 the Northern Pacific Railroad had reached Portland, Oregon. Roads were built over or near most of the trail as local travelers traveled to cities originally established along 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, by raft, and by boat to establish new farms, lives, and businesses in the Oregon Country. This territory in the early 19th century was subject to competing claims by the United States and Britain (United Kingdom), who had come to an arrangement usually described as "joint occupancy"; Britains name for the region was the Columbia District, referring to the local regional department of the Hudsons Bay Company.

The four- to six-month journey spanned over half the continent as the wagon trail led about convert2000mikmabbr=off west through territories and land that later became six U.S. states: 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 (Washington (U.S. state)), and Montana.