The prominent American explorer best known for his journey through the Louisiana Purchase is Meriwether Lewis. Alongside William Clark, Lewis led the famed Lewis and Clark Expedition from 1804 to 1806. This journey aimed to explore the newly acquired territory after the Louisiana Purchase and to establish trade and relations with Native American tribes. The expedition provided invaluable insights into the geography, biology, and cultures of the region, significantly contributing to the understanding of the American frontier. Lewis's adventurous spirit and leadership marked a pivotal moment in American exploration history.