The most remote area explored by mountain men in the 1820s and 1830s was the Oregon country, the region consisting of present-day Oregon and Washington. In the 1830s and 1840s, Americans living east of the Mississippi River began to hear about the Oregon country from missionaries. Beginning in 1843, wagon trains set out for Oregon each summer from settlements along the Missouri River.
Americans' interest in Oregon and California country grew with each passing year, as the emigrants sent letters back home describing the region to their friends and family. After the discovery of gold in California in 1848, an even larger group of people set out on the overland trails for California.
Whether traveling to Oregon or California, the emigrants found that overland travel was difficult and filled with danger. The pioneers and their animals were worn out at the end of their journey.
To find more American Memory sources on this topic, search the collections using such terms as overland journeys to the Pacific, frontier and pioneer life [by state], exploration, surveys, and guidebooks [by state], or using specific geographical or human-made features of the area (e.g., Platte River, Snake River, Fort Laramie).