Two members of the Clark family bore the same name: 1) William Clark (d. 1791), a son of Benjamin and thus a first cousin of George Rogers Clark; and 2) William Clark (1770-1838), youngest brother of George Rogers Clark. The elder William was a member of his cousin's Illinois Regiment and remained in military service until 1784. Afterwards he became commissioner for the Illinois grant and secretary of its governing board and at the time of his death was its principal surveyor. The younger William, a child at the time of the Revolution, soldiered in later Indian campaigns in the Old Northwest serving under John Hardin (1789), Charles Scott (1791), and Anthony Wayne (1792-1796). Accepting an invitation from Meriwether Lewis, Clark joined in planning and commanding the famed Lewis and Clark Exposition (1805-1806). Later he saw both military and civil service as governor of Missouri Territory (1813-1821) and spent the latter years of his life (1822-1838) coping with Indian problems encountered as superintendent of Indian affairs in St. Louis.
