The journey of Lewis & Clark was one of the greatest adventures in American history. Follow the four-year journey of these two explorers and their team as they traveled from St. Louis to the Pacific Coast and back. President Thomas Jefferson commissioned Lewis & Clark to explore the Louisiana Purchase—new land west of the Mississippi that the United States had bought from France in 1803. With the vital help of their Indian guide Sacajawea, the Corps of Discovery gathered scientific data about the land, climate, plants, and animals along the way. They also established relations with at least two dozen Indian tribes during their journey. Use the interactive map to follow the journey of Lewis & Clark and read entries from their journals. View their extensive list of supplies, including medical equipment and gifts for Native Americans. And, read the biographic portraits of some of the key members of the Corps.