 Hillyer saw extensive fighting at Fredericksburg (briefly commanding the regiment) and Gettysburg, where he fought at the famed "Wheatfield" on July 2, 1863.The 9th Georgia lost half of its 340 men in the fight, and Hillyer's company suffered considerable losses.With all the senior officers wounded or killed, Hillyer assumed command of the regiment for the rest of the Gettysburg Campaign, and wrote the official report of the 9th Georgia's service in the battle.