In 1803, Meriwether Lewis recruited William Clark to colead Thomas Jefferson’s government expedition along the Missouri River, across the Louisiana Purchase, and to the Pacific Ocean. During their expedition (1804–6), Lewis and Clark gathered information that gave the United States an edge in trade and political negotiations. The resulting interest in the West led the government to authorize numerous acts that forced the removal of Native populations.
During his travels to paint portraits of Native Americans, George Catlin visited Clark, a go-to source of information. Having previously served
as governor of the Missouri Territory (1812–21), Clark was then superintendent of Indian Affairs in St. Louis (1822–38). Catlin’s painting shows Clark resting his hand on the recently negotiated fourth Treaty of Prairie du Chien (1830), which ceded Indigenous lands to the federal government and established the Nemaha Half-Breed Reservation for descendants of French-Canadian trappers and Indigenous women.