What was the main goal of the Lewis and Clark expedition?

The Lewis and Clark expedition, commissioned by President Thomas Jefferson following the Louisiana Purchase in 1803, primarily aimed to explore the newly acquired western territory. This exploration was crucial for gaining a better understanding of the geography, resources, and potential for expansion in the vast lands west of the Mississippi River. It also provided valuable information about the indigenous peoples and the wildlife of the region. While the expedition did involve mapping and establishing relationships with various Native American tribes, the overarching goal was to document and survey the newly acquired territory, paving the way for future settlement and development.

The other options may touch on aspects of the expedition's activities but do not encapsulate its primary purpose. Establishing trade with Native Americans was a component of their interactions but not the primary objective. Mapping the Atlantic coastline was unrelated to their journey, which focused on the interior of the continent. Finding a route to the Pacific Ocean was indeed part of their mission, but the broader objective of exploring and surveying the entire western territory aligns more directly with the motivations articulated by Jefferson for the expedition.