CONFIDENTIAL.] HEADQUARTERS CAVALRY CORPS,

Warrenton Junction, Va., June 8, 1863.

Brigadier General D. McM. GREGG,

Commanding Second and Third Cavalry Divisions:

GENERAL: You will move to your command to-day in such manner as to be able to act with them at daylight in the morning (to-morrow) to cross the Rappahannock River at Kelly's Ford. On arriving at Kelly's Ford you will find Brigadier General D. A. Russell, with a command of 1,500 infantry and one horse battery, which force will be under your orders for ensuing operations. At daylight of the 9th instant you will cross your whole command of infantry, cavalry, and artillery over the Rappahannock River at Kelly's Ford as expeditiously as possible. A couple of boats will be at the ford under your orders, to enable you to cross some infantry above or below the ford, to drive away the enemy's pickets attempting to annoy you. Unless there is the most urgent necessity for it, do not use your artillery in effecting a crossing, as it would only apprise the enemy of your advance. Have no bugle or other calls sounded until further orders. As soon as you have crossed the river, move on as rapidly as possible, keeping yoru force well in hand, and masking the infantry with your cavalry and by the forests to prevent the enemy from observing it. When your infantry have crossed Kelly's Ford, direct it to move on Brandy Station. The cavalry will extend to the right as far as that point, with itsd line in the direction and as far as Stevensburg. It is expected that by the time your right is near Brandy Station, you will be in communication with the other forces of the expedition. If this is the case, you will then, while moving forward your right in the direction of Culpeper, swing round your left to envelop such of the enemy's forces as may be east and south of Culpeper. Brigadier-General Russell's command will act with General Ames' command on reaching Brandy Station, and form a distinct command under the orders of Brigadier-General Russell. General Russell's command will follow the cavalry movement to Culpeper. General Barnes, of the Fifth Corps, at Kelly's Ford, will be directed to cross 500 men to the opposite side of the river and put themselves in communication with your force at Stevensburg, to protect your flank from attack. You will place in position at Stevensburg at least one regiment of cavalry and two pieces of artillery, with especial instructions to look out for Raccoon Ford. You will also throw out strong pickets in the direction of Ely's and the Germanna Fords, who will give timely notice to Barnes' infantry of any approach of the enemy in that direction. Should you hear very heavy firing with troops not of your command, hasten to their assistance. Headquarters will move with the infantry and cavalry on the right until they arrive at Brandy Station. After that the headquarters will be with the infantry command, unless circumstances require a change, when you will be duly notified. Endeavor to communicate with the command on your right as soon after crossing as possible. It gives me great pleasure to state, general, you have my entire confidence in the execution of these duties. Keep me fully advised of your progress.

I am, general, very respectfully, your obedient servant,

A. PLEASONTON,

Brigadier-General, Commanding.

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