Settlers heading west in the early part of the nineteenth century were advised to keep their wagonloads light, so heavy atlases were left at home, with guidebooks and newspaper articles often serving as substitutes. Detailed maps such as the Ornamental Map of the United States and Mexico or Johnson’s Family Atlas served more to inspire settlers westward than as actual navigational tools. Rather, wagon parties often hired experienced guides, sometimes former fur trappers, who knew the journey well and could help them make the crossing. The first major wagon train of this nature departed from St. Louis in 1843, under the direction of John Gantt, and contained between 700 and 1,000 emigrants.
John C. Fremont, a military officer and explorer heralded by the press of his day as “The Pathfinder,” undertook several westward expeditions in the 1840s to survey and create maps of the western United States. His first expedition began in 1842 and was succeeded in the following year by a more rigorous expedition with a crew of surveyors and cartographers. This expedition, along with two subsequent forays, provided a wealth of details about what is now known as the Oregon Trail.