From 1804 to 1806, Captains Meriwether Lewis and William Clark led about 40 soldiers and boatmen on an epic journey after President Thomas Jefferson commissioned this Corps of Discovery to find a route to the Pacific Ocean through the newly acquired Louisiana Territory. Along the way, they mapped the land, recorded its resources, and contacted its native inhabitants. Since their exploration, rivers have been dammed, forests cut over, prairies plowed under, and roads built to the horizon, though remnants of wilderness still remain.