What was probably the most important result of the expedition by Lewis and Clark?

The most important result of the Lewis and Clark expedition was the comprehensive mapping and exploration of the western territories of the United States, which greatly expanded the nation’s understanding of the geography, resources, and potential for westward expansion. Their findings facilitated subsequent migration and settlement, contributing to the idea of Manifest Destiny. Additionally, the expedition established diplomatic relations with various Native American tribes and laid the groundwork for future exploration and development in the region.