two US explorers who made the Lewis and Clark Expedition in 1804–5. President Thomas Jefferson sent Meriwether Lewis (1774–1809) and William Clark (1770–1838) to lead an investigation of America’s new Louisiana Purchase and record what they saw. They left from St Louis in 1804, reached the Pacific Ocean 18 months later, and then returned in 1806. Their journey encouraged many Americans to move to the West. The story of it was told in the film The Far Horizons (1955).
See also Sacajawea .