University of Virginia
Lewis and Clark: Maps of Exploration 1507 1814
An online resource from the University of Virginia Library. This exhibition includes maps, documents, and a great overview map collections from the first images of the New World to maps from the Lewis and Clark Expedition.
PBS
Pbs: The West: Lewis and Clark Expedition
Part of the PBS site, "The West," this link gives a general explanation of the Lewis and Clark expedition. Links to biographies.