Colonel Bissell's regiment (2d Illinois) which had been joined by a section of Captain Sherman's battery, had become completely outflanked, and was compelled to fall back, being entirely unsupported. The enemy was now pouring masses of infantry and cavalry along the base of the mountain on our left, and was gaining our rear in great force. At this moment I arrived upon the field. The Mississippi regiment had been directed to the left before reaching the position, and immediately came into action against the Mexican infantry which had turned our flank. The 2d Kentucky regiment, and a section of artillery under Captain Bragg, had previously been ordered from the right to re-enforce our left, and arrived at a most opportune moment. That regiment, and a portion of the 1st Illinois, under Colonel Hardin, gallantly drove the enemy, and recovered a portion of the ground we had lost. The batteries of Captains Sherman and Bragg were in position on the plateau, and did much execution, not only in front, but particularly upon the masses which had gained our rear. Discovering that the enemy was heavily pressing upon the Mississippi regiment, the 3d Indiana regiment, under Colonel Lane, was despatched to strengthen that part of the line, which formed a crotchet perpendicular to the first line of battle. At the same time Lieutenant Kilburn, with a piece of Captain Bragg's battery, was directed to support the infantry there engaged. The action was, for a long time, warmly sustained at that point, the enemy making several efforts, both with infantry and cavalry, against our line, and being always repulsed with heavy loss. I had placed all the regular cavalry, and Captain Pike's squadron of Arkansas horse, under the orders of Brevet Lieutenant-Colonel May, with directions to hold in check the enemy's column, still advancing to the rear along the base of the mountain, which was done in conjunction with the Kentucky and Arkansas cavalry under Colonels Marshall and Yell.
In the mean time our left, which was still strongly threatened by a superior force, was farther strengthened by the detachment of Captain Bragg's, and a portion of Captain Sherman's batteries to that quarter. The concentration of artillery fire upon the masses of the enemy along the base of the mountain, and the determined resistance offered by the two regiments opposed to them, had created confusion in their ranks, and some of the corps attempted to effect a retreat upon their main line of battle. The squadron of the 1st Dragoons, under Lieutenant Rucker, was now ordered up the deep ravine which these retreating corps were endeavoring to cross, in order to charge and disperse them. The squadron proceeded to the point indicated, but could not accomplish the object, being exposed to a heavy fire from a battery established to cover the retreat of those corps. While the squadron was detached on this service, a large body of the enemy was observed to concentrate on our extreme left, apparently with the view of making a descent upon the hacienda of Buena Vista, where our train and baggage were deposited. Lieutenant-Colonel May was ordered to the support of that point, with two pieces of Captain Sherman's battery under Lieutenant Reynolds. In the mean time, the scattered forces near the hacienda, composed in part of Majors Trail and Gorman's commands, had been, to some extent, organized under the advice of Major Munroe, chief of artillery, with the assistance of Major Morrison, volunteer staff, and were posted to defend the position. Before our cavalry had reached the hacienda, that of the enemy had made its attack; having been handsomely met by the Kentucky and Arkansas cavalry under Colonels Marshall and Yell. The Mexican column immediately divided, one portion sweeping by the depot, where it received a destructive fire from the force which had collected there, and then gaining the mountain opposite, under a fire from Lieutenant Reynolds' section, the remaining portion regaining the base of the mountain on our left. In the charge at Buena Vista, Colonel Yell fell gallantly at the head of his regiment; we also lost Adjutant Vaughan, of the Kentucky cavalry, a young officer of much promise. Lieutenant-Colonel May, who had been rejoined by the squadron of the 1st Dragoons, and by portions of the Arkansas and Indiana troops, under Lieutenant-Colonel Roane and Major Gorman, now approached the base of the mountain, holding in check the right flank of the enemy, upon whose masses, crowded in the narrow gorges and ravines, our artillery was doing fearful execution.
The position of that portion of the Mexican army which had gained our rear was now very critical, and it seemed doubtful whether it could regain the main body. At this moment I received from General Santa Anna a message by a staff officer, desiring to know what I wanted. I immediately dispatched Brigadier-General Wool to the Mexican general-in-chief and sent orders to cease firing. Upon reaching the Mexican lines, General Wool could not cause the enemy to cease their fire, and accordingly returned without having an interview. The extreme right of the enemy continued its retreat along the base of the mountain, and finally, in spite of all our efforts, effected a junction with the remainder of the army.
During the day, the cavalry of General Minon had ascended the elevated plain above Saltillo, and occupied the road from the city to the field of battle, where they intercepted several of our men. Approaching the town, they were fired upon by Captain Webster from the redoubt occupied by his company, and then moved off towards the eastern side of the valley, and obliquely toward Buena Vista. At this time Captain Shover moved rapidly forward with his piece, supported by a miscellaneous command of mounted volunteers, and fired several shots at the cavalry with great effect. They were driven into the ravines which lead to the lower valley, closely pursued by Captain Shover, who was farther supported by a piece of Captain Webster's battery, under Lieutenant Donaldson, which had advanced from the redoubt, supported by Captain Wheeler's company of Illinois volunteers. The enemy made one or two efforts to charge the artillery, but was finally driven back in a confused mass, and did not again appear upon the plain.
In the mean time, the firing had partially ceased upon the principal field. The enemy seemed to confine his efforts to the protection of his artillery, and I had left the plateau for a moment, when I was recalled thither by a very heavy musketry fire. On regaining that position, I discovered that our infantry (Illinois and 2d Kentucky) had engaged a greatly superior force of the enemy, evidently his reserve, and that they had been overwhelmed by numbers. The moment was most critical. Captain O'Brien, with two pieces, had sustained this heavy charge to the last, and was finally obliged to leave his guns on the field, his infantry support being entirely routed. Captain Bragg, who had just arrived from the left, was ordered at once into battery. Without any infantry to support him, and at the imminent risk of losing his guns, this officer came rapidly into action, the Mexican line being but a few yards from the muzzles of his pieces. The first discharge of canister caused the enemy to hesitate, the second and third drove him back in disorder, and saved the day. The 2d Kentucky regiment, which had advanced beyond supporting distance in this affair, was driven back and closely pressed by the enemy's cavalry. Taking a ravine which led in the direction of Captain Washington's battery, their pursuers became exposed to his fire, which soon checked and drove them back with loss. In the mean time, the rest of our artillery had taken position on the plateau, covered by the Mississippi and 3d Indiana regiments, the former of which had reached the ground in time to pour a fire into the right flank of the enemy, and thus contribute to his repulse. In this last conflict we had the misfortune to sustain a very heavy loss. Colonel Hardin, 1st Illinois, and Colonel McKee and Lieutenant-Colonel Clay, 2d Kentucky regiment, fell at this time while gallantly leading their commands.
No further attempt was made by the enemy to force our position, and the approach of night gave an opportunity to pay proper attention to the wounded, and also to refresh the soldiers, who had been exhausted by incessant watchfulness and combat. Though the night was severely cold, the troops were compelled for the most to bivouack without fires, expecting that morning would renew the conflict. During the night the wounded were removed to Saltillo, and every preparation made to receive the enemy, should he again attack our position. Seven fresh companies were drawn from the town, and Brigadier-General Marshall, with a re-enforcement of Kentucky cavalry and four heavy guns, under Captain Prentiss, 1st Artillery, was near at hand, when it was discovered that the enemy had abandoned his position during the night. Our scouts soon ascertained that he had fallen back upon Agua Nueva. The great disparity of numbers, and the exhaustion of our troops, rendered it inexpedient and hazardous to attempt pursuit. A staff officer was dispatched to General Santa Anna to negotiate an exchange of prisoners, which was satisfactorily completed on the following day. Our own dead were collected and buried, and the Mexican wounded, of which a large number had been left upon the field, were removed to Saltillo, and rendered as comfortable as circumstances would permit.
On the evening of the 26th, a close reconnoissance was made of the enemy's position, which was found to be occupied only by a small body of cavalry, the infantry and artillery having retreated in the direction of San Luis Potosi. On the 27th, our troops resumed their former camp at Agua Nueva, the enemy's rear guard evacuating the place as we approached, leaving a considerable number of wounded. It was my purpose to beat up his quarters at Encarnacion early the next morning, but upon examination, the weak condition of the cavalry horses rendered it unadvisable to attempt so long a march without water. A command was finally dispatched to Encarnacion, on the 1st of March, under Colonel Belknap. Some two hundred wounded, and about sixty Mexican soldiers were found there, the army having passed on in the direction of Matehuala, with greatly reduced numbers, and suffering much from hunger. The dead and dying were strewed upon the road and crowded the buildings of the hacienda.
The American force engaged in the action of Buena Vista was 344 officers and 4,425 men, exclusive of the small command left in and near Saltillo. Of this number, two squadrons of cavalry and three batteries of light artillery, making not more than 453 men, composed the only force of regular troops. The strength of the Mexican army is stated by General Santa Anna, in his summons, to be 20,000; and that estimate is confirmed by all the information since obtained. Our loss is 267 killed, 456 wounded, and 23 missing. Of the numerous wounded, many did not require removal to the hospital, and it is hoped that a comparatively small number will be permanently disabled. The Mexican loss in killed and wounded may be fairly estimated at 1,500, and will probably reach 2,000. At least 500 of their killed were left upon the field of battle. We have no means of ascertaining the number of deserters and dispersed men from their ranks, but it is known to be very great.
Our loss has been especially severe in officers, twenty-eight having been killed upon the field. We have to lament the death of Captain George Lincoln, Assistant Adjutant-General, serving in the staff of General Wool, a young officer of high bearing and approved gallantry, who fell early in the action. No loss falls more heavily upon the army in the field than that of Colonels Hardin and McKee, and Lieutenant-Colonel Clay. Possessing, in a remarkable degree, the confidence of their commanders, and the last two having enjoyed the advantage of a military education, I had looked particularly to them for support in case we met the enemy. I need not say that their zeal in engaging the enemy, and the cool and steadfast courage with which they maintained their positions during the day, fully realized my hopes, and caused me to feel yet more sensibly their untimely loss.
I perform a grateful duty in bringing to the notice of the government the general good conduct of the troops. Exposed for successive nights, without fires, to the severity of the weather, they were ever prompt and cheerful in the discharge of every duty; and finally displayed conspicuous steadiness and gallantry in repulsing, at great odds, a disciplined foe. While the brilliant success achieved by their arms releases me from the painful necessity of specifying many cases of bad conduct before the enemy, I feel an increased obligation to mention particular corps and officers, whose skill, coolness and gallantry in trying situations, and under a continued and heavy fire, seem to merit particular notice.