HEADQUARTERS THIRD ARMY CORPS,
Buckland Mills, August 27, 1864-11.30 p.m.

It being understood that a large division of the enemy under Longstreet left Salem at 4 o'clock p.m. for the enemy's position in the direction of Manassas, through Thoroughfare Gap, and is now on the march, the following preliminary movements of the left wing of the army will be immediately made, and Major-General Sigel's corps will without delay be concentrated at or near Hay Market and Gainesville. A division of the Third Corps will be left at Buckland Mills to operate against the flanks of the enemy or march to Hay Market, as shall be found most expedient. King's and Rickett's divisions will march to Gainesville, and start at 2 o'clock a.m., to attack the enemy's position in the direction of Manassas. This attack will be supported under the provision of the general order from headquarters of the Army of Virginia by the command of Major-General Heintzelman, now at Greenwich, and which will be on the right of the attack.

By command of Major-General McDowell:

S. F. BARSTOW,

Assistant Adjutant-General.

This order was written by me in General Sigel's room at Buckland Mills after a full conversation with him, and embodied the result of that conversation. General Sigel had gone to sleep while I was writing, and not wishing to disturb him (for we all needed rest when we could get it) I went to my camp and gave the rough of the order to a staff officer to put in form and carry into effect; but before I thought he had done so I received the following order from General Pope:

UNITED STATES MILITARY TELEGRAPH,

(Received at Bristoe Station August 27, 1862, 9 p.m.)

Major-General McDOWELL:

At daylight to-morrow morning march rapidly on Manassas Junction with your whole force, resting your right on the Manassas Gap Railroad, throwing your left well to the east. Jackson, Ewell, and A. P. Hill are between Gainesville and Manassas Junction. We had a severe fight with them to-day, driving them back several miles along the railroad. If you will march promptly and rapidly at the earliest dawn of day upon Manassas Junction we will bag the whole crowd. I have directed Reno to march from Greenwich at the same hour upon Manassas Junction, and Kearny, who is in his rear, to march on Bristoe at daybreak. Be expeditious and the day is our own.

JNO. POPE,

Major-General.

This caused a change to be made in the preliminary dispositions I had directed, and the following order wa issued:

GENERAL ORDERS,
HEADQUARTERS THIRD ARMY CORPS,

No. 10. Reynolds' Camp, August 28, 1862.

1st. Major-General Sigel will immediately march with his whole corps on Manassas Junction, his right resting on the Manassas Railroad.

2nd. Brigadier-General Reynolds will march on the turnpike immediately in rear of General Sigel, and form his division on the left of General Sigel, and march upon Manassas Junction.

3rd. Brigadier-General King will follow immediately after General Reynolds, and form his division on General Reynolds' left, and direct his march upon Manassas Junction.

4th. Brigadier-General Ricketts will follow Brigadier-General King, and march to Gainesville, and if, on arriving there, no indication shall appear of the approach of the enemy from Thoroughfare Gap, he will continue his march along the turnpike, form on the left of General King, and march on Manassas Junction. He will be constantly on the lookout for an attack from the direction of Thoroughfare Gap, and in case one is threatened, he will form his division to the left and march to resist it.

The headquarters of the corps be at King's division.

By command of Major-General McDowell:

ED. SCHRIVER,

Colonel and Chief of Staff.

This is the order for the march of the troops from Buckland Mills to