The history of the settlement of Oregon Country in the United States is a fascinating tale of exploration, hardship, and determination. Following the Louisiana Purchase in 1803, the US government aimed to open up Oregon Country, which included present-day Oregon, Washington, and part of Idaho, to settlement. In 1803, Lewis and Clark's US government funded expedition charted the first, albeit hazardous route that was not feasible for families traveling by wagon. In 1810, Robert Stuart of the Astorians became the first white man to use a different, more comfortable route that came to be known as the Oregon Trail. His 2,000-mile journey from Fort Astoria to St. Louis took 10 months to complete.Marcus and Narcissa Whitman led a missionary party from Missouri to Oregon in 1836 and made the use of wagons. In 1843, the "Great Migration" was organized, a wagon train of nearly 1,000 people setting out from Independence, Missouri made it to Oregon without incident. This train used a 12-mile wide valley, called South Pass, to cross the Rocky Mountains. With the settlement of thousands in Oregon Country, in 1846, the British ceded Oregon Country to the United States.