The Battle of Cross Keys took place on Sunday, June 8, 1862, and was the first major battle in which the Thirteenth officially took part. Following its training during the winter of 1862, the battery participated during the Spring in numerous deployments throughout the Shenandoah Valley and along the Rappahonnock River. These deployments typically summoned them to accompany reconnaissance details, or as reinforcements for minor skirmishes which were often over by the time they arrived. In June the Battery was sent to Cross Keys as part of General Steinwehr's brigade, under command of Colonel Koltes, along with the Twenty-ninth and Sixty-eighth New York and the Seventy-third Pennsylvania Infantry. Arriving at the battle, they took position, but saw little action as the main fighting soon developed along other parts of the battlefield. In a letter to his mother, Lieut. William Wheeler describes the battery's involvement. (Note that Wheeler sometimes uses the term "we" or "our" to refer to the Thirteenth Battery, and at other times to the Union forces).

MOUNT JACKSON, VA., June 12, 1862.

DEAREST MOTHER, — After the passage of about ten days I write you from the same place from which I wrote to J., but you must not think that this interval of time has been spent in rest here. On the contrary, we have made forced marches in the direction of Staunton, have fought a battle, and have made a rapid retreat, and reached this place at about noon to-day, a thoroughly used up set both of men and horses. However, I managed to snatch a little sleep this afternoon, and feel quite wide-awake this evening, so I eagerly seize this opportunity to let you hear from me, not knowing what the morrow may bring forth, nor how suddenly we may have to march again. ....Be sure that I shall take good care of my health, and shall not expose my life except when duty demands it, and if I fall in the performance of that duty, you will know that it so pleased the Director of all events, and will not sorrow unduly at my dying in the noblest way, and for the highest and best cause. You will wish to know something about our recent movements. About eight days ago the pontoon bridge over the Shenandoah at this point was finished, and our army moved across and marched rapidly after Jackson, who was still but a short distance in advance of us. If we could have saved the bridge and if the rains had not raised the river too high to prevent our immediately rebuilding it, we should have caught this prince of bushwhackers, together with the train and prisoners which he took from Banks. But the elements seemed completely against us, and we lost him by about a day. The second day's march brought us to Harrisonburg. Here we shod our horses, and got everything in readiness for the approaching fight. On Saturday night our cavalry made an attack on the Rebs, but were met by a much larger force than they had expected, and were driven back with loss. On Sunday we marched out in full force to beat up his quarters; the women gazed at us, as we marched through the town, their eyes streaming with tears, for it was their own husbands and sons and brothers that we were to meet in mortal combat. By 10 A.M. the heavy thunder of the cannon showed that the work had commenced, and that our advance was engaged, and soon the rolling fire of musketry told us that it had come to closer quarters. General Schenk's Ohio Brigade had the extreme right wing; then came General Milroy's Virginia, then our First Brigade in the centre, then the Third Brigade, and lastly our Brigade, the Second, on the left wing; this was our position in the afternoon. Our right wing pushed their left wing back; in the centre the fire was very hot, and Blenker's own regiment, the Eighth New York, suffered dreadfully, being exposed to a galling fire from a whole brigade under cover, while they stood out in a wheat field; still they maintained their ground gallantly and were well supported by Schirmer's Battery, which did great execution. On the left the Third Brigade was just going to charge the enemy, and were aching for the encounter, when they were withdrawn and we were ordered up at double quick to support them. We had got into a piece of meadow among the woods, and were about to clear the woods and turn the enemy's flank, when our Brigade was also withdrawn, not having fired a shot. Our Battery had no orders to retire, so we stood still while the infantry drew to the rear. For a little while we were in great peril, — we were between the fire of one of our own batteries and the enemy's infantry, — still our men were very cool and collected, and only wanted a chance to do something. Towards night the firing ceased, and we encamped on the border of the battle-field, our Battery covering the left wing from the top of a high hill. The enemy sloped during the darkness, and in the morning was "non est inventus," so we, who were in the extreme advance, lost the chance of distinguishing ourselves. It was a pretty equal fight. Our loss in killed and wounded must have been six hundred. That of the enemy could not have been less than one thousand, as our artillery cut some of his regimnts up badly. Had our two brigades, which hardly fired a shot, been allowed to go into the fight, the result would have probably been far different, and our victory would have been thorough and complete. Still it cannot be denied that this Jackson is a man of decided genius, and that very few in our army are fit to compete with him. Thus on Tuesday he fought our army and prevented our further advance, in the night he crossed the bridge, which he burned after him to prevent us from following, and, having received reënforcements under Longstreet, beat back Shields who was advancing on the other side of the river. On Tuesday his combined force returned against us, now treble our number, and we were forced to retreat. Our Brigade was the rear-guard, and I had the honor to cover the extreme rear with my section. The road was about the worst I ever saw. When I had got about six miles I found several of our heavy caissons almost hopelessly bemired; the captain told me to send my section on, and gave me the pleasant task of fetching on those caissons. It was an awful job, as you may imagine. As the horses had had no feed for two days, they were very weak; but I persevered, and marched through Harrisonburg at three in the morning with everything safe and sound. A rest until 8 A.M., and then we marched again, luckily on a good road, or our poor horses would have fallen dead; here we hope for rest and feed and food and reënforcements: it is also said that General Sigel is to take command of the Corps. If he does, I feel the most perfect confidence that we shall end this doubtful campaign with brilliant victories. I will not harrow up your sensibilities by speaking of the horrors of the battlefield. It was bad enough to have seen them without repeating. I had an opportunity, during a halt, of tending a whole barnful of our wounded soldiers, some of them with three bullets in them; one poor fellow pierced by seven, and yet not seriously injured. They all agreed in the statement that they had been very kindly treated by most of the enemy among whom they fell, — a few acting barbarously, but the most with tender and delicate humanity. This makes me feel more kindly to our erring brothers than before. Would that we could join hands and be friends once more. I am in excellent health, but have not known what it was to be dry. At night I have flung myself down by the nearest fire without blankets and have slept sweetly, regardless of deep mud or pouring rain. I love you all as much as ever, if I am a shabby, muddy soldier, worn out with hard work, and unable, from sheer fatigue, to write you an interesting or satisfactory letter.