On the morning of the 29th, the Division maneuvred into a position opposing Jackson on what Gilbreath called "roughly the same ground on which the Battle of Bull Run had been fought a year earlier", with the major difference being the position of the two armies was reversed. The 20th Indiana's position during the battle was on the extreme right flank of the Union lines. Gilbreath mentions that this relieved the regiment from the more severe part of the fighting, however the regiment still lost about the same number of men as the rest of the units in the battle. Most of the regiment's losses occurred during the initial advance from the Union positions towards the railroad, which served as a sort of breastwork for the defending Confederate army. Upon securing this position, the regiment wheeled left and hid among the undergrowth along the railroad. This order was given by General Kearney in an attempt to relieve pressure in the center of the Union battle line, which was beginning to break up. The Confederate forces charged this line, bypassing the 20th Indiana without noticing them. At some point during this, Gilbreath's company opened fire from their hiding spot and charged the advancing enemy in the flank. I Company's counterattack was immensely successful, taking the Confederates completely by surprise and forcing them to withdraw from the immediate area. Shortly after this action Colonel Brown, commander of the regiment, was shot through the head by a Confederate sharpshooter. Major John Wheeler, previously commander of B Company, assumed command of the regiment.