The Lewis and Clark Expedition was commissioned to explore the newly acquired western territories of the United States, particularly the land acquired in the Louisiana Purchase.

The Lewis and Clark Expedition (1804-1806) was a U.S. government-sponsored expedition to explore the newly acquired Louisiana Purchase and the lands west to the Pacific Ocean. Their primary objectives were to map the territory, establish trade with Native American tribes, and find a practical water route to the Pacific. Their journey provided invaluable geographical and scientific information about the vast western expanse of North America.