While posted along the railroad between Manassas and Warrenton Junction, companies B, G and H were captured by the Confederates. The 1st and Hooker's divisions were engaged at Bristoe Station on August 29. The following day, the entire army was in action at Second Bull Run, where once more the gallant work of the 105th resulted in significant losses. The regiment was specially complimented by Maj. Gen. Philip Kearny for its gallantry. September and October were spent at Washington. The command left the nation's capital on October 28, and, after some scouting near Leesburg, arrived at Falmouth on November 24. The 105th's next battle was at Fredericksburg, after which it spent the winter in camp near Brandy Station.