Brigadier General George Washington Cullum served as Chief of Staff to General Henry W. Halleck during the U.S. Civil War. Cullum was a prominent American military engineer and author, best known for his work on the annual publications "Register of the Army" and "Annual Report of the Chief of Engineers". In this role under Halleck, Cullum played a significant part in the administrative and logistical aspects of the Union army during one of the most crucial periods in U.S. history.