Numbers 166. Report of Brigadier General A. Sanders Piatt, U. S. Army, commanding First Brigade.

HEADQUARTERS PIATT'S BRIGADE,
Near Falmouth, Va., December 16, 1862

CAPTAIN: I have the honor to report that I resumed my command on the evening of the 11th instant.

On the morning of the 12th, by direction, my brigade took its place in the division column and moved toward the middle bridge over the Rappahannock. Before reaching this, in pursuance of further orders, we retraced our steps and crossed the Rappahannock at the upper bridge and entered the town of Fredericksburg. The head of my column, upon reaching the top of the bank at Fredericksburg, was forced to halt, on account of a number of troops that were massed in the street. While in this condition, the enemy's batteries opened and commenced shelling the column. I immediately changed the head of my column to the right, and placed the first regiment under cover of the river bank: the two remaining regiments, under my instructions, given through one of my aides, took shelter under the opposite bank of the river. The enemy's batteries ceased firing, when in obedience to orders, I recrossed the river and encamped for the night.

On the morning of the 13th, in pursuance of orders received, my brigade again occupied the advance in the column; crossed the river and took position up the river and on the right of the bridge, placing us on the right flank of the Army of the Potomac. Masking my troops under the hill, I immediately proceeded to relieve the pickets on the extreme right, belonging to General Sully's brigade. This picket consisted of a regiment the line starting perpendicularly to the river; thence bearing to the left and running equidistant from the enemy's works from the first change in direction to the left, till it rested on the right of the Twelfth New Hampshire Volunteers, commanded by Colonel Potter. On making a reconnaissance of the ground in front, I found it advantageous to push the picket lines farther forward, and it was done, on the road that lay between the canal and the race. In this position everything remained until dark, when I placed the Excelsior Battery in position to command the open ground in front, and the other two regiments to the right and left, to support it in case of an attack during the night. Late at night, when the firing ceased, the men lay down in line and slept by their arms.

Of the energy of the officers under my command, and the coolness of the men throughout the whole battle of the 13th, while the shells were flying in every direction over them and bursting among them I cannot speak too highly.

I had the misfortune, by the stumbling of my horse and the loosening of the saddle-girth, to be precipitated to the ground, injuring my back so severely as to render me unable to walk since.

The remainder of the report will be rendered by Colonel Franklin, who took command of the brigade, I being unable to remain upon the field, and have been reported unfit for duty since the morning of the 14th.

Respectfully submitted.

A. SANDERS PIATT,

Brigadier-General, Commanding First Brigade, Third Division.

Captain HENRY R. DALTON, Assistant Adjutant-General.