Rebellion Record: a Diary of American Events: Documents and Narratives, Volume 11.
Frank Moore, Ed.

[614] of Frederick City, Maryland, which resulted in the battle of Monocacy, fought ninth July last. The informal report telegraphed Major-General Halleck from Ellicott's Mills, during the retreat, is appended hereto, and will serve to make the record complete.

The situation in the department of West Virginia about the beginning of July was very uncertain. Major-General Hunter had retreated westwardly from Lynchburg, leaving open the Shenandoah Valley, up which a column of rebels of unknown strength had marched, and thrown General Sigel back from Martinsburg to Williamsport, thence down the left bank of the Potomac to Maryland Heights, where, with his command, he was supposed to be besieged. The strength of the invading column, by whom it was commanded, what its objects were, the means provided to repel it — everything, in fact, connected with it — were on my part purely conjectural. All that I was certain of was that my own department was seriously threatened.

July fifth, information was brought to my headquarters in Baltimore that a column of rebel cavalry — the same that had been raiding in the border counties of Pennsylvania--was in the Middletown Valley, moving eastwardly. Taking this report as true, the enemy had turned his back upon the department of Major-General Couch, and reduced his probable objectives to Washington, Baltimore, or Maryland Heights.

In this situation I felt it my duty to concentrate that portion of my scanty command available for field operations at some point on the Monocacy river, the western limit of the Middle Department. With an enemy north of the Potomac, and approaching from the west, having in view any or all the objectives mentioned, the importance of the position on which I ultimately gave battle, cannot be over-estimated. There, within the space of two miles, converge the pikes to Washington and Baltimore, and the Baltimore and Ohio railroad; there, also, is the iron bridge over the Monocacy, upon which depends railroad communication to Harper's Ferry. Moreover, as a defensive position for an army seeking to cover the cities above named against a force marching from the direction I was threatened, the point is very strong; the river covers its entire front: in a low stage of water, the fords are few, and particularly difficult for artillery; and the commanding heights are all on the eastern bank, while the ground on the opposite side is level and almost without obstructions. At all events, I was confident of ability to repel any ordinary column of cavalry that might be bold enough to attack me there; and if the position should be turned on the right, I was not necessarily disabled from defending Baltimore; in that contingency, I had only to take care of the railroad, and use it at the right time. Accordingly, I went out and joined General Tyler at the railroad bridge. The information received in Baltimore was confirmed; rebel cavalry had seized Middletown; their scouting parties had even advanced to within three miles of Frederick City. By the evening of the sixth all my available troops were concentrated under General Tyler, making a force of scant twenty-five hundred men of all arms, and composed as follows: Third regiment (Md.) Potomac Home Brigade, Colonel Charles Gilpin; Eleventh (Md.) infantry, Colonel Landstreet; seven companies of the One Hundred and Forty-ninth, and three companies of the Hundred and Fifty-ninth Ohio National Guard, consolidated, temporarily, under Colonel A. L. Brown; Captain Alexander's (Md.) battery, and one hundred men of the Hundred and Fifty-ninth Ohio National Guard, serving as mounted infantry, and commanded by Captain E. H. Lieb, Fifth United States Cavalry, and Captain N. S. Allen. In addition, I had the service of Lieutenant-Colonel Clendenin's squadron of cavalry, two hundred and fifty men, and four companies of the First regiment (Md.) Potomac Home Brigade, about two hundred strong, under Captain Brown. Of this force, it is proper to add, the Eleventh Maryland, and all the Ohio troops, were “hundred-days men.”

On the night of the sixth Colonel Clendenin received my order to take the pike to Middletown, and follow it until he found the enemy, and ascertained the strength and composition of his column. Leaving Frederick City at daybreak next morning (the seventh) with his cavalry, and a section of Alexander's battery, he drove in a rebel outpost stationed in the mountain pass, and gained Middletown, where he was stopped by a body of cavalry largely superior to his own, commanded by General Bradley T. Johnson. After a smart skirmish, in which both sides used artillery, Clendenin was forced back by movements on his flanks. About ten o'clock he reported the rebels one thousand strong, pushing him slowly to Frederick City, which they would reach in two hours, unless I intended its defence. Though out of my department, it had become my duty to save the town, if possible, and as it was but three miles distant, I thought that could be done without jeopardizing the position at the railroad bridge. By direction, therefore, General Tyler sent Colonel Gilpin, with his regiment and another gun, to support Clendenin, and engage the enemy. The company of mounted infantry also went forward. In this movement the railroad was very useful.

Colonel Gilpin reached the town in good time, and deployed his command in skirmish order across the Hagerstown pike, half a mile west of the suburbs. Clendenin fell back and joined him. About four o'clock P. M. the enemy opened the fight with three pieces of artillery. The lines engaged shortly after. At six o'clock Captain Alexander, personally in charge of his pieces, dismounted one of Johnson's guns. A little before dark Gilpin charged, and drove the rebels, who, under cover of night, finally withdrew to the mountain.

You will find the locality of this action indicated