Oregon National Historic Trail - http://www.nps.gov/oreg

As the harbinger of America's westward expansion, the Oregon Trail was the pathway to the Pacific for fur traders, gold seekers, missionaries and others. Beginning in 1841 and continuing for more than 20 years, an estimated 300,000 emigrants followed this route from Independence, Missouri to Oregon City, Oregon on a trip that took five months to complete.
The 2,170 mile long trail passes through Missouri, Kansas, Nebraska, Wyoming, Idaho and Oregon.