Thomas Jefferson commissioned the Lewis and Clark Expedition in 1803 to explore the northwest territory in order to observe a transcontinental route and natural resources. In 1804, about 45 men headed by Meriwether Lewis and William Clark moved up the Missouri River, crossed the Rocky Mountains, and from the Columbia River, reached the Pacific Ocean by November 1805. They returned to St. Louis by September 1806 with great fanfare and important information on native people, plants and animals, and geography.
As Jefferson groomed Meriwether Lewis to head an expedition to explore the West, it was understandable that he would turn to fellow members of the American Philosophical Society for support. This was the oldest learned society in the United States, and one dedicated to furthering knowledge of the natural sciences as well as cultivating the arts.