HDQRS. MIDDLE DEPARTMENT, EIGHTH ARMY CORPS,
Baltimore, August-, 1864.

COLONEL: I beg leave to furnish the War Department with the following report in full of the operations of my command in the vicinity of Frederick City, Md., which resulted in the battle of Monocacy, fought 9th 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 object were, the means provided to rebel 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 5, information was brought to my headquarters in Baltimore that a column of rebels 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 overestimated. There, within the space of two miles, converge the pikes to Washington and Baltimore, and the Baltimore and Ohio Railroad; there also is 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 division 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 rebel 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 Frederick City. By the evening of the 6th all my available troops were concentrated under General Tyler, making a force of scant 2,500 men of all arms, and composed as follows: Third Regiment Mary-

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*See p. 191.

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13 R-VOL XXXVII, PT I