No. 55. Report of Brigadier General Winfield S. Hancock, U. S. Army, commanding First Division.

HEADQUARTERS HANCOCK'S DIVISION,
Falmouth, Va., December 25, 1862.

MAJOR:During the evening of the 10th instant, I was instructed to send two regiments of infantry, the Fifty-seventh New York Volunteers, Lieutenant-Colonel Chapman commanding, and the Sixty-sixth New York Volunteers, Lieutenant-Colonel Bull, commanding, to the Lacy house, immediately opposite Fredericksburg, in order that they might serve as a protecting party to the engineers engaged int he construction of the pontoon bridges, which were to be erected there in the course of the ensuing morning, and to march with the remainder of my division, at 6 a.m., to a point on the railroad near the bridge over which the division was to cross the Rappahannock.

These orders were complied with, the troops being massed by 8 a.m. on the 11th at the place designated, and the two regiments detached arriving at the Lacy house shortly after midnight. During the operations of the 11th instant, Lieutenant-Colonel Chapman, of the Fifty-seventh New York Volunteers, was severely wounded. Many valuable officers and men, in the aggregate 150, were killed and wounded in these two regiments while they were engaged in protecting the working parties.

Late in the afternoon of the 11th instant, orders were received to cross the river at Fredericksburg, by the third bridge. The division moved to effect that object, but, finding that the bridge was not completed, the troops were ordered into bivouac.

The next morning, the 12th instant, at daylight orders were received to march the entire division into Fredericksburg across the second bridge.

At 8 a.m. the division had arrive at that bridge and commenced the passage, the troops of General French's division crossing the upper bridge at the same time. My division was then formed in line of battle, on the street nearest the river, with the left resting on the third bridge, over which the Ninth Corps then commenced marching. French's division formed the second line in my front, and Howard's the first line, in a street nearer the enemy.

At a later hour orders were received to march by the left flank across Hazel Run, thence down the Rappahannock, forming in the rear of General Franklin's grand division, my division taking the lead, and each division of the corps marching in three parallel lines of brigades, the Ninth Corps marching parallel to us, and between our line and the river. To perform this maneuver it became necessary to erect bridges over Hazel Run. Three bridges were constructed. Subsequently it was determined to defer this movement until the next morning.

About 8 a.m. on the 13th instant, I was notified by Major-General Couch, commanding Second Army Corps, that General French's division would attack the enemy in front of the town, and that my division would support him. The formation for the attack was prescribed int he orders received: Brigade front, intervals between the brigades of 200 paces. I first relieved the pickets of General French's division by two regiments of my own, instructing them, however, to reform and join in the assault after General French's skirmishers had driven in the opposing pickets.