On 14 May, Lewis and Clark set off on their expedition to explore what is now the northwest of the United States. The trip had been ordered by President Thomas Jefferson.
Editors. "The Lewis and Clark Expedition". The Literary Encyclopedia. First published 01 February 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=4380, accessed 22 May 2013.]