Meriwether Lewis and William Clark led the U.S. Corps of Discovery on an historic expedition across the uncharted western lands of North America in the early 1800s. Tasked by President Thomas Jefferson to map the territory, discover its flora and fauna, and establish friendly trade relationships with native tribes; Lewis and Clark journeyed more than 8,000 miles for two years, from Missouri to the Pacific Ocean. Their discoveries directed the future course of American exploration and expansion. Through two primary source activities and a short video, students will understand what this expedition meant for the future United States of America.