William Clark's Grave - Only a few short miles from the site of Camp Dubois, where he spent the winter of 1803-04, is the grave of William Clark. This site is located on a terrace of the Mississippi River overlooking that river and very near the mouth of the Missouri River. In the past 200 years both the Missouri and Mississippi's courses have changed. (Lewis and Clark, 12/12/1803-5/14/1804)