Four members of the Lewis & Clark Expedition view the Missouri River from a promontory. The expedition was the first government-sponsored crossing and exploration of the North American continent, beginning in 1803. Its mission was to study the natural constitution of the land recently acquired from France and to note any territorial aspirations of other nations.

Expedition members Meriwether Lewis, William Clark, York, Sacagawea, and Lewis's Newfoundland dog, Seaman, are included in the monument.