No. 2. Report of Major General S. P. Heintzelman, U. S. Army.

HEADQUARTERS DEPARTMENT OF WASHINGTON,
Washington, July 20, 1863.

GENERAL: I understand that no report has been made of the crossing of the Potomac at the Long Bridge and occupation of Arlington Heights and Alexandria on the morning of the 24th of May, 1861.

I was at that time acting inspector-general to Brigadier General J. K. F. Manfield, commanding the Department of Washington, and as the troops that crossed the bridge moved under my direction, I have the honor to make the following report:

On the afternoon of the 23rd, I went with General Mansfield to the Engineer Department, and he there explained to me the plan of operations. This, I understood from him, did not include the occupation of Alexandria. Before the troops moved, however, this part of the plan was changed.

The troops which crossed, from the original manuscript now in my possession [were]:

By the Aqueduct. - Staff commanding Captain Wood, now Major W. H. Wood, Seventeenth U. S. Infantry. Engineers Woodbury, Blunt, and Houston. Forty-eight pioneers of Fourteenth Regiment New York, Colonel Wood; Sixty-ninth Regiment New York, Colonel Corcoran, and 250 workmen, unarmed; Fifth Regiment New York, Colonel Schwartzwalder; Twenty-eighth Regiment New York, Colonel Burns; one company cavalry; one section artillery.

By the Long Bridge. - Staff commanding Colonel Heintzelman. Engineers Alexander, Prime, and Robert. Twelfth Regiment New York, Colonel Butterfield; Twenty-fifth Regiment New York, Colonel Bryan; Seventh Regiment New York, Colonel Lefferts; Third Regiment New Jersey, General Runyon; one company cavalry; one section artillery.

By steamer.- First New York Zouaves, Colonel Ellsworth. This regiment was encamped on the Potomac below the Eastern Branch, and was landed on the wharves of Alexandria under the guns of the gunboat Pawnee.

Also by the Long Bridge. - First Michigan and Pioneers, Colonel Willcox; one company cavalry; one section artillery.

Captain Brackett commanded the company of cavalry (I, Second Cavalry) that crossed the Long Bridge, and the artillery, I think, belonged to Major T. W. Sherman's battery.

During the day I warned the regiments to be prepared to march at a moment's notice, and at 9 p. m. officers were sent to the colonels, directing them to march their troops to the Washington end of the Long Bridge.

The orders were to enter on the bridge at 2 a. m. on the 24th of May. A few minutes before the hour the head of the column halted at the Washington end of the bridge, and precisely at the hour the troops advanced, the Twelfth New York, Colonel Butterfield, leading. Colonel C. P. Stone, in command of the District Volunteers, had made such admirable arrangements that he was enabled to take possession of the Virginia end of the bridge before any alarm was given, and thus prevented the rebels front firing it. He immediately pushed forward on the different roads strong pickets. On the road towards Arlington they extended as far as the bridge across the canal.

Captain S. Owen, who commanded some of the District Cavalry, accompanied