The Oregon Trail was a roughly 2,000-mile route from Independence, Missouri, to Oregon City, Oregon, that was used by hundreds of thousands of American pioneers in the mid-1800s to emigrate west. The trail was arduous and snaked through Missouri and present-day Kansas, Nebraska, Wyoming, Idaho, and finally into Oregon. Without the Oregon Trail and the passing of the Oregon Donation Land Act in 1850, which encouraged settlement in the Oregon Territory, American pioneers would have been slower to settle the American West in the 19th century.

Source: History