It shared the fortunes of Pope's Bull Run campaign, was in position at Elk Mountain on the 17th of September, during the Battle of Antietam, and subsequently, after performing a variety of fatiguing duties, marched with Franklin's corps to a position in front of Fredericksburg. In the assault upon that city, December 14, it acted with spirit and efficiency. In the preliminary movements of Franklin's corps, this Regiment was the first to cross the river, in face of a heavy body of rebel infantry and artillery, and deploying as skirmishers, drove in their pickets- a movement executed with the coolness and precision of a regimental drill. Here, Colonel Wheaton was ordered to the command of a brigade that had been under the command of General Howe, and the command of the Regiment devolved on the gallant Colonel Nelson Viall, who received his commission on the field. This he subsequently resigned, and the temporary command of the Regiment fell to Lieutenant-Colonel Goff, an able and highly esteemed officer. He was succeeded by Colonel Horatio Rogers, Jr.,transferred from the 11th R. I. Volunteers.