Louis, and the 1905 Lewis and Clark Centennial Exposition, in Portland, Oregon, showcased Lewis and Clark as American pioneers. Both the 1904 Louisiana Purchase Exposition, in St. Lewis and Clark began to gain new attention at the turn of the century. References to Lewis and Clark "scarcely appeared" in history books even during the United States Centennial in 1876 and the expedition was largely forgotten despite having had a significant impact on increasing American owned land. Although the expedition did make notable achievements in science, scientific research itself was not the main goal behind the mission. The success of their journey helped to strengthen the idea that United States territory was destined to reach all the way to the Pacific. They found Native Americans in the trans-Mississippi West accustomed to dealing with European traders and already connected to global markets. Although Lewis and Clark failed to find a commercial route to Asia, they demonstrated the possibility of overland travel to the Pacific coast. Reports about geography, plant and animal life, and Indian cultures filled their daily journals. They returned in 1806, bringing with them an immense amount of information about the region as well as numerous plant and animal specimens.
After crossing the Rocky Mountains, the expedition reached the Pacific Ocean in the area of present-day Oregon (which lay beyond the nation's new boundaries) in November 1805. They were accompanied by a fifteen-year-old Shoshone Indian woman, Sacagawea, the wife of a French-Canadian fur trader. sovereignty over the Native Americans along the Missouri River, and getting an accurate sense of the resources in the recently-completed Louisiana Purchase.
Jefferson also placed special importance on declaring U.S. According to Jefferson himself, one goal was to find a "direct & practicable water communication across this continent, for the purposes of commerce with Asia" (the Northwest Passage). Their objects were both scientific and commercial – to study the area's plants, animal life, and geography, and to discover how the region could be exploited economically. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William Clark, the expedition had several goals. The Lewis and Clark Expedition, or ″Corps of Discovery Expedition"(1804–1806) was the first transcontinental expedition to the Pacific Coast by the United States.