On the 23d of May, at midnight, the regiment was put in motion and marched down through the city, to the neighborhood of the Long Bridge. Its departure had been quiet and noiseless, as if the expedition were a secret to all but the commanding officer. It soon appeared, however, from signs that the uninitiated are not slow to comprehend, that something more was going on than the night march of the regiment. The order to halt came from other sources to our own commander. After some delay, a part of the New Jersey brigade came up from the rear and passed on in advance; and there was riding here and there of officers and messengers, going and coming in various directions. Nevertheless, everything was done in silence. Not even the occupants of the neighboring houses seemed to be awakened or disturbed; and it gave to the scene a mysterious kind of interest to feel that we were on some errand that neither friends nor enemies were to know of until it was accomplished.
Again our column was on the march, and we soon found ourselves at the entrance of the Long Bridge. We passed between the two guard-houses, under the black timbers of the draw-frame, and over its three quarters of a mile of roadway to the Virginia shore. It was the first hour of a moonlight night, and half a mile farther on, at daybreak, the regiment was halted and went into bivouac on an open field by the roadside.
Not long after sunrise a horseman came clattering along the road from the direction of Alexandria, and as he galloped by toward the bridge, he flung out to us the news, "Alexandria is taken, and Colonel Ellsworth is killed."
This was one of the minor events in the early part of the war that excited a wide-spread interest, mainly from the dramatic features of the incident. The Eleventh New York had reached Alexandria by steamer, and landed there about daylight. Immediately after disembarking, Colonel Ellsworth had left his regiment, and with a small squad hastened to secure the telegraph office, to prevent communication with the south. That done, he noticed, flying above the principal hotel in the town, a secession flag. It was the flag we had seen so often for the last fortnight from the direction of Washington. The colonel effected an entrance, and with his companions mounted to the roof, hauled down the flag, and brought it away with him. When about halfway down he was shot dead by the keeper of the hotel, who was lying in wait for him with a double-barreled gun. Instantly the soldier next him discharged his musket in the face of the homicide, and, driving his bayonet through his breast, hurled his body down the remaining stairway; so that within a minute both the colonel and his assailant were dead men. None of those in the hotel knew of the arrival of the regiment, and probably thought they had to do only with a few raiders from abroad.
This news of the occupation of Alexandria was our first intimation of the actual extent of the movement we were engaged in. The truth was that between midnight and dawn about 12,000 men had crossed the Potomac by the two bridges at Washington and Georgetown, beside the Eleventh regiment which went by steamer. They were to hold and fortify a defensive line extending from below Alexandria, around Arlington Heights, to the Potomac River above Georgetown; comprising, when all complete, a chain of twenty-three forts, for the permanent security of the city on its southern side. Our own destination was a locality not far from our first bivouac, and where the New Jersey troops, who had gone before, were already breaking ground for the trenches.
Next day the men of the Seventh were also set to work with pick and spade and barrow, excavating the ditch and piling up the rampart along the lines laid down by the engineers. One fatigue party followed another, all doing their best, like so many ants on an ant-hill; and before night the place began to look something like a fortification. When finished it was the largest of those on the south side of the river, occupying a space of about fourteen acres. It was an inclosed bastioned work, covering the two forks of the road; one leading south to Alexandria, the other southwest toward Fairfax Court House. It defended the Long Bridge, and secured its possession for ingress and egress. It was named Fort Runyon, in honor of the general commanding the New Jersey brigade.
After a few days on the Virginia shore, the regiment was ordered back to its camp at Meridian Hill. It had been mustered into service for one month, to meet an emergency which was now past. Orders for its return north were received on the 30th of May; and on the 31st it broke camp and embarked for New York, arriving there on the 1st of June. It was then mustered out of service, having been under arms forty-three days.
This was the "Washington campaign" of the Seventh regiment. It was a campaign without a battle, and the regiment was not once under fire from the enemy. Its only casualties were one man killed in camp by the accidental discharge of a musket, and another wounded in the leg by his own pistol. But it came to the front at a time when one battalion for the moment was more needed than a brigade afterward. Though mustered out as a regiment, it at once began to supply material for other organizations. Of its members in 1861, more than six hundred entered the service during the war; over fifty became regimental commanders; from twenty to thirty, brigadier-generals; and more than one reached the grade of major-general. With all this depletion, its ranks were kept tolerably full by new recruits, and it was twice afterward called into the field for temporary duty, once in 1862, and again in 1863.