The famous pioneer of the American West known for leading settlers across the Oregon Trail was John C. Frémont. A topographer, soldier, and politician, Frémont explored and mapped significant regions of the western United States during the 1840s. His expeditions were critical in promoting the idea of westward expansion, and he played an instrumental role in encouraging settlers to migrate along the Oregon Trail. Frémont's adventurous spirit and contributions to exploration enticed thousands to seek new opportunities in the frontier, shaping America’s westward journey.