Thomas Jefferson sent Lewis and Clark on an expedition so that trade could be established with western Native American people and so that they could also find a water route to the Pacific Ocean. Before Jefferson became president, he wanted to send explorers on an expedition across North America.
Jefferson sent a letter to Congress in Jan. 18, 1803, asking for $2,500 in order to fund the Lewis and Clark expedition. Meriwether Lewis was chosen by Jefferson to lead the expedition because he had the necessary skills, military discipline and experience. Lewis chose Clark, a former rifleman whom he had served with in his company, to aid him in leading the U.S. Army expedition, which is known today as the Corps of Discovery.