The Regular cavalry battalion at Bull Run was not heavily engaged. It lost 13 men wounded and 5 missing. It was commanded by Maj Innis Palmer, 2nd Cav (later 5th Cav). It consisted of 1 company of the 2nd Dragoons (later 2nd Cav) commanded by future Confederate general F. C. Armstrong, 2 Companies of the 1st Cav (later 4th Cav), and 4 companies of the 2nd Cav (later 5th Cav) with which Custer served at the battle.