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The Lewis and Clark expedition was the first American expedition through the west of the nation, going from the city of Saint Louis to the Pacific coast, seeking a waterway that connects the East Coast with the Pacific, as well as consolidating sovereignty American over the region.
The expedition was carried out at the behest of President Thomas Jefferson, who sought to consolidate American dominance over the Louisiana Territory, which had recently been purchased from France. This lasted from 1804 to 1806, and not only consolidated American sovereignty over the area, but also allowed scientists to learn about the different animal and plant species in the area and the establishment of trading posts near native territories.