For how long did Archibald Henderson serve as Commandant of the Marine Corps?

Archibald Henderson served as the Commandant of the Marine Corps for 38 years, from 1820 until his death in 1859. This long tenure is notable in the history of the Marine Corps because it allowed him to shape the organizational structure and operational philosophy of the Corps during a critical period of its development. Henderson is often credited with modernizing the Marine Corps and expanding its role within the U.S. military, and his influence extended well beyond his time in office. The length of his service exemplifies a period of stability and growth for the Marine Corps, which is why the figure of 38 years is recognized as correct in historical records.