The Lewis and Clark Expedition, the first European-American overland exploring party to reach the Pacific Coast, was led by Meriwether Lewis and William Clark, following the Louisiana Purchase of 1803. Between 1804 and 1806, its members journeyed from St. Louis to the Oregon coast and back, providing information and dispelling myths about the large area acquired by the United States in the Purchase. The Portland fair commemorated the centennial of that trip.