Irvin McDowell
John Adair McDowell (1825–1887) was an American military officer and engineer who served as the first colonel of the 6th Iowa Volunteer Infantry Regiment during the American Civil War. He was a younger brother of Irvin McDowell, the general best remembered for the First Battle of Bull Run, the first large Civil War battle. He was also the son of Abram Irvin McDowell, a former mayor of Columbus, Ohio.