Report of Maj. Gen. Alexander McD. McCook, U.S. Army, commanding Twentieth Army Corps. AUGUST 16-SEPTEMBER 22, 1863.--The Chickamauga Campaign.

Chattanooga, October 2, 1863.

Chief of Staff.

       GENERAL: I have the honor to submit a detailed account of the operations of the Twentieth Army Corps, from the date of constructing the pontoon bridge over the Tennessee River at Caperton's Ferry, on the 29th of August, 1863, until the occupation of Chattanooga by the Army of the Cumberland.
       At 4 a.m., August 29, the pontoons were ready for the construction of the bridge over the Tennessee River. Heg's brigade, of Davis' division, of this corps, was placed in the boats and crossed to the opposite bank to cover its construction, to drive away the enemy's pickets, and to seize the heights of Sand Mountain. This duty was well performed, and the bridge completed at 1 p.m.
       Carlin's brigade, assisted by 100 men and officers of the Pioneer Corps, guarded the bridge.
       August 30, General Davis crossed his remaining two brigades, concentrating them at the foot of Sand Mountain.
       Johnson's division, of the Twentieth Corps, stationed at Bellefonte, Ala., marched to the ford at Crow Creek, and Davis' entire division encamped on night of the 30th on top of Sand Mountain. Sheridan's division assisted in building a bridge at Bridgeport, Ala., to enable it to cross the river at that point. His line of march was via Trenton, Ga., thence to Will's Valley.
       August 31 Johnson's division crossed the river at Caperton's Ferry and encamped at foot of Sand Mountain.
       September 1 headquarters of corps at Stevenson, Ala.
       September 2 Davis' division advanced and encamped at the foot of Sand Mountain, in Will's Valley. Johnson's division moved up the mountain and encamped near the western summit. Sheridan's division crossed at Bridgeport and marched toward Trenton.
       September 3 Davis in camp in Will's Valley. Johnson marched to near eastern summit of Sand Mountain. Headquarters of corps with this division. The First and Second Divisions of cavalry passed this point at 1 p.m.
       September 4 Davis marched to Winston's, foot of Lookout Mountain, and seized the pass over the mountain at that place. Johnson's division marched down the Sand Mountain and encamped on the ground vacated by Davis.
       Winston's is 42 miles from Chattanooga, 25 miles from Caperton's Ferry, 48 miles from Rome, Ga., and 45 miles from Dalton, Ga.
       September 5 General Sheridan reported his command to be encamped a few miles southwest of Trenton, having been delayed by Negley's wagon train.
       September 6 Sheridan encamped at Stevens' Mill, 12 miles from Winston's.
       September 7 no movements.
       September 8 Johnson's division marched to Long's Spring, on the Trenton road, and two bridges of Davis' division were ordered into Broomtown Valley, to support Stanley's cavalry.
       September 9 Carlin's brigade, of Davis' division, marched on Alpine, Ga., to support the cavalry. Heg's brigade of same division marched toward Broomtown Valley, by way of Neal's Gap. At 6 p.m. I received information from the general commanding, stating that the enemy had evacuated Chattanooga, and were retreating southward, and ordering me to move rapidly upon Alpine and Sum-merville, Ga., in pursuit; to intercept his line of retreat and attack him on flank.
       September 10 Post's brigade, of Davis' division, was ordered to remain at Winston's, to guard trains, &c. Johnson's division marched at 5 a.m. from Long's Spring, and crossed Lookout Mountain, encamping at base near Henderson's. Sheridan's division marched at 5 a.m. from Stevens' Mill, and encamped on Little River, about 2 miles from the western crest.
       Headquarters of the corps moved to near Alpine.
       On arriving at Alpine I discovered that the enemy had not retreated very far from Chattanooga, and not being able to communicate with General Thomas by way of the valley, I dispatched couriers by way of Valley Head and learned to my surprise that he had not reached La Fayette as ordered. His reasons for not having reached that place became more apparent as we progressed. Under these circumstances I did not move upon Summerville as ordered.
       My corps was isolated at Alpine, and had it moved to Summerville it would have been exposed to the entire rebel army, which reconnaissance soon convinced me was being concentrated at or near La Fayette, Ga.
       September 11, 9.30 p.m., I received communication from General Thomas, repeating his difficulties on the march, and that he could not reach La Fayette until the 12th. Believing that no co-operation could exist between General Thomas and myself by way of Broomtown Valley, I ordered all my wagon trains and materiel not absolutely necessary for the troops to be returned to the top of Lookout Mountain, and there to await the result of the cavalry reconnaissance sent by General Stanley to ascertain the whereabouts of the enemy, the general commanding being apprised of my movements and dispositions.
       September 12 the Twentieth Corps rested in position near Alpine.
       September 13 orders were received from General Thomas at midnight, directing two divisions of my corps to be moved to his support, and the other division to be left to guard the trains. This order was given by direction of General Rosecrans. It was my desire to join General Thomas by the Mountain road via Stevens Gap, but not having any guide, all the citizens concurring that no such road existed, and General Thomas also stating that the route by Valley Head was the only practicable one, I determined to join him by that route. A brigade from each division was detailed as a guard for my trains and General Lytle placed in command. My corps was moved up the mountain at Alpine.
       On the night of the 13th and on the night of the 14th my corps was again encamped in Lookout Valley, except the division guarding the trains, which was encamped at Little River, on the mountains. Sheridan's division marched down Lookout Valley to Johnson's Crook, and encamped at the base of the mountains.
       Being informed that a good mountain road ran direct from Valley Head to Stevens' Gap, Generals Johnson and Davis were ordered to march on that road with the utmost expedition.
       By direction of the general commanding, General Lytle was ordered to move with two brigades to the head of McLemore's Cove to observe Dougherty's Gap.
       On the 17th my corps was concentrated in McLemore's Cove, Sheridan being posted at the foot of Stevens' Gap, Davis at Brood's [Brooks'], in front of Dug Gap, Johnson at Pond Spring, in front of Catlett's Gap, in Pigeon Mountain. My instructions were to concentrate my corps between Pond Spring and Gower's, on Chickamauga Creek. It was impossible for me to comply with these orders, as General Thomas' corps occupied the ground. My instructions were subsequently modified.
       On the 18th General Lytle arrived with his two brigades, and on the night of the 18th my corps was closed up compactly upon the Fourteenth Corps with the exception of Post's brigade of Davis' division, which was by the direction of the general commanding ordered to hold Stevens' Gap, in Lookout Mountain, at all hazards.
       Subsequently Colonel Post was ordered to report to General R. B. Mitchell, commanding the cavalry, and did not report to General Davis until his arrival at Chattanooga on the morning of the 22d of September.
       September 19, at 12.15 a.m., I was ordered to move down to Crawfish Spring with the Twentieth Corps as soon as General Thomas' troops were out of the way.
       In compliance with this order Johnson's division marched at early dawn, followed by Davis' and Sheridan's divisions. I arrived at Crawfish Spring at an early hour, and reported in person to the general commanding, who ordered me to mass my troops at that place and await further orders. This was done as General Johnson's troops arrived.
       At 10.15 a.m. I was ordered to take command of the right and the cavalry, including Negley's division of the Fourteenth Corps, then observing two fords of Chickamauga Creek near Crawfish Spring, one brigade of this division being then engaged with the enemy. The same order directed me to send General Johnson's division forward to Widow Glenn's house to report to General Thomas. Immediately afterward I received instructions to send General Davis' division, also, to the Widow Glenn's house to report to General Thomas or the general commanding. These orders were at once complied with.
       By this time the advance of Sheridan's division came up, and as soon as he was posted to support the right of Crittenden's corps at Gordon's Mills, General Negley's division was withdrawn from the fords of Chickamauga Creek, and by the direction of the general commanding ordered to report to General Thomas, which he did. This left me with but one division, Sheridan's, and the cavalry (which had not been heard from) to take care of the right.
Learning from an aide-de-camp of General Wood Lieutenant Yaryan) that General Wood's troops had been withdrawn from Gordon's Mills, and appreciating the great importance of that point, General Sheridan's division was at once ordered to take position there, and arrived just in time to prevent the enemy from crossing.
       Subsequently an order reached me from the general commanding to hold the position at Gordon's Mills.
       At 3 p.m. I received an order to send two brigades of Sheridan's division to the Widow Glenn's house, leaving the First Brigade, General Lytle's, at Gordon's Mills; also directing me, should the right be secure, to go forward in person and take command of the troops of the corps already engaged.
       General R. B. Mitchell reporting with his cavalry, I was enabled to obey this order at once, arriving upon the field at the close of the engagement of the 19th.
       On the 19th General Johnson's division fought near the extreme left of the line of battle. His division fought gloriously, driving the enemy more than a mile, capturing seven of the enemy's guns and a large number of prisoners.
       General Davis' division fought on the right of Widow Glenn's house against vastly superior numbers, maintaining the conflict gallantly until near nightfall, when it was relieved by Bradley's brigade, of Sheridan's division, which was hastily thrown forward and gallantly drove the enemy from the open ground and across the Chattanooga and La Fayette road, after a sanguinary engagement, recapturing the Eighth Indiana Battery, which had been previously captured by the enemy, and capturing also a large number of prisoners belonging to Hood's division, of Longstreet's corps. Darkness coming on the battle closed.
       At midnight of the 19th of September I received the following order:

Widow Glenn's, September 19, 1863--11.45 a.m.

Major-General McCOOK,
Commanding Twentieth Army Corps:

       The general commanding directs you as soon as practicable after the receipt of this order to post your command so as to form the right of the new battle front, and hold this place. Leave your outposts and grand guard where they now are till they are driven in by the enemy, when they will fall back on the main body of your command, contesting the ground inch by inch.

Very respectfully,
Brigadier-General, and Chief of Staff.

       The date of the above order should be read 11.45 p.m.
       This order was strictly complied with. Lytle's brigade, of Sheridan's division, was posted on the strong position in rear of Glenn's house, Sheridan's other two brigades were posted on very strong ground to the right and rear of this position. Davis' division, consisting of two small brigades, was posted to the left and rear of this position, in reserve, his left resting on the right of Crittenden's corps. These movements were all completed by daylight of the 20th, when the general commanding visited my position in person. Johnson's division was still retained near the extreme left of the line of battle and not under my immediate orders.
       At 6 a.m. of the 20th Col. J. T. Wilder, Seventeenth Indiana, commanding brigade of mounted infantry, reported in person to me, stating that he had with his troops been ordered to join my command and receive orders from me, also stating that he had two regiments armed with the Spencer rifle posted in the woods on the right of Negley's position, which was to the left and front of General Lytle's position. The remainder of Colonel Wilder's command, with its artillery, was posted on strong ground immediately to Sheridan's right.
       At about 7 a.m. the following was received:

McDonald's, September 20--6.35 a.m.

Major-General McCooK,
Commanding Twentieth Army Corps:

       General Negley's division has been ordered to General Thomas' left. The general commanding directs you to fill the space left vacant by his removal, if practicable. The enemy appears to be moving toward our left.

Very respectfully, your obedient servant,
Brigadier-General, and Chief of Staff.

       Immediately upon receipt of this order, Major-General Sheridan and myself rode to the position vacated by General Negley's division. We found nearly all this space already occupied by General Wood's division. He informed me that his left rested on General Brannan's right, and that his orders were to close up on General Brannan.
       Discovering that a portion of the rude barricades on Wood's right was not occupied by our troops, I ordered General Sheridan to bring forward one of his brigades to fill up the space between Wood's left and Wilder.
       On turning from this position I met General Davis' division marching toward and about 100 yards from the vacant barricades on Wood's right, he informing me that he had been ordered there by General Rosecrans. Seeing his position and knowing the advantage of occupying the barricades at once, I directed him to place one brigade there, holding the other in reserve.
       On the arrival of the brigade from Sheridan's division it was posted in column on Davis' right and rear as his support. Davis' instructions were to keep well closed up to the left.
       These instructions being just completed, the following order was received:

In the Field, September 20,1863--10.10 a.m.

Major-General McCOOK,
Commanding Twentieth Army Corps:

       General Thomas is being heavily pressed on the left. The general commanding directs you to make immediate disposition to withdraw the right so as to spare as much force as possible to re-enforce Thomas. The left must be held at all hazards even if the right is withdrawn wholly back to the present left. Select a good position back this way and be ready to start re-enforcements to Thomas at a moment's warning.

Brigadier-(General, and Chief of Staff.

       Within five minutes after the receipt of the above order, and instructions given to carry it out, the following order was received:

In the Field, September 20, 1863--10.30 a.m.

Major-General McCooK,
Commanding Twentieth Army Corps:

       The general commanding directs you to send two brigades of General Sheridan's division at once and with all possible dispatch to support General Thomas, and send the third brigade as soon as the lines can be drawn in sufficiently. March them as rapidly as you can without exhausting the men. Report in person to these headquarters as soon as your orders are given in regard to Sheridan's movement.
       Have you any news from Colonel Post?

Brigadier-General, and Chief of Staff.

       This order was executed at once. Two brigades of Sheridan's division, Lytle's and Walworth's, were taken from the extreme right, and were moving at the double-quick to the support of General Thomas. Simultaneously with this movement, and much to my surprise, Wood's division left the position it held in line of battle on Davis' left, marching by the left flank, leaving a wide gap in the line of battle. An attempt was made by General Davis to fill up the space thus vacated. Buell's brigade, of Wood's division, had scarcely marched more than its length when a most furious and impetuous assault was made by the enemy, in overwhelming numbers, on this portion of the line, the enemy's lines of battle extending from beyond Brannan's right to a point far to the right of the Widow Glenn's house, and in front of the strong positions just abandoned by General Sheridan's two brigades.
       To resist this attack I had but two brigades of Davis' division (numbering about 1,200 men), and Colonel Laiboldt's brigade, of Sheridan's division, as a support. Finding the enemy pouring through the interval between Davis and Brannan, Lytle's and Walworths brigades were deflected from their line of march to the left, and ordered to assist in resisting the enemy.
       Colonels Wilder and Harrison, with their commands, closed in on Sheridan's right as speedily as possible, and did good service. General Davis' command, being overwhelmed by numbers, was compelled to abandon its position in order to save itself from complete annihilation or capture. Laiboldt's troops, moving up to Davis' support, met with a similar fate.
       The other two brigades of Sheridan's division were illy prepared to meet such an attack. They struggled nobly, and for a time checked the enemy in their immediate front, but the position being turned far to the left they were compelled to withdraw from the unequal contest.
       It was thus that these five brigades of the Twentieth Corps were cut off and separated from the remainder of the Army of the Cumberland. No troops fought with more heroism or suffered greater losses than these rive small brigades, their loss being over 40 per cent. of the number engaged in killed and wounded.
       In regard to the numbers of the enemy that attacked on the right I can make no estimate. General Sheridan captured prisoners from five different rebel divisions.
       The Fifty-first Illinois, of Walworth's brigade, captured the colors of the Twenty-fourth Alabama.
       The troops of Generals Sheridan and Davis' divisions were rallied a short distance in rear of the line of battle and marched toward Rossville to endeavor to form a junction with the troops under General Thomas. Their presence was reported to General Thomas by my chief of staff, Lieutenant-Colonel Thruston.
       These troops were placed in position by order of General Thomas, on the road leading from the battle-field to Rossville. During the night they withdrew to Rossville with the remainder of the army. The Second Division of the Twentieth Corps, under General R. W. Johnson, fell back to Rossville with the Fourteenth Corps, Willich's brigade forming the rear guard.
       On the night of September 20 the Twentieth Army Corps was united in good order at Rossville.
       On the morning of the 21st, a short time after daylight, the corps was again Put in line of battle, the left resting on Mission Ridge, covering the Crawfish Spring road, the right extending toward Chattanooga Creek and Lookout Mountain.
       The corps remained in this position until 2 a.m. on the morning of the 22d of September, when it was withdrawn to Chattanooga with the rest of the army.
       Since arriving at Chattanooga the Twentieth Corps has been engaged in performing heavy guard duty and erecting strong lines of intrenchments, which, in my opinion, can only be taken by regular approaches.
       My thanks are due to Col. Joseph C. McKibbin, Capt. A. S. Burt, Capt. R. S. Thoms, and Lieut. George Burroughs, of General Rosecrans' staff, for valuable assistance in rallying the portions of Sheridan's and Davis' divisions which had been overwhelmed.
       Brig. Gen. J. St. C. Morton, chief engineer of the Army of the Cumberland, being separated from his chief, reported to me for duty.
       After ascertaining that the center of our line had been broken, my first object was to endeavor to find the general commanding to ascertain to what point he wished the rallied troops marched. Failing to find the general and believing that an efficient stand could not be made by the army until it reached Chattanooga, the firing on the left retiring toward Rossville, from the statements of General Rosecrans' guides, and from observations by General Morton, I was satisfied that the enemy was endeavoring to cut our army off from Rossville. At this juncture, Lieut. Col. Lyne Starling, of General Crittenden's staff, rode up and reported to me that his chief had gone to Chattanooga to report to General Rosecrans. I then decided to report to General Rosecrans at once for instructions as my last order from his headquarters required.
       Finding the general commanding at Chattanooga, he directed me to go out on the road to Rossville, collecting all the troops possible, and report to General Thomas.
       Leaving Chattanooga at midnight I arrived at Rossville at about 4 a.m. on the morning of the 21st, when the line of battle above referred to was formed, and strong barricades erected.
       The conduct of the troops of the Twentieth Corps was everything that could be expected of men.
       During the two days' battle Johnson's division fought on the left, separated from the corps. All acknowledge the gallantry of his division. He never attacked that he was not successful, and the enemy never assaulted him without being handsomely repulsed. I depend upon General Thomas and the official reports to do this gallant division justice.
       The troops of Sheridan's and Davis' divisions, behaved with great courage, never yielding except to overwhelming numbers when it would have been suicidal to have contested the ground longer.
       To the families of the heroic dead the sympathies of the nation are due. Such names as Lytle, Heg, Baldwin, brigade commanders, Colonels Alexander, Gilmer, McCreery, and many other distinguished field and line officers, who fell upon this memorable field, will make a brilliant page in our history as a nation.
       These expressions should also extend to the many non-commis-sioned officers and privates who gave their lives in defense of their country and flag.
       To Maj. Gen. P. H. Sheridan, commanding Third Division; Brig. Gen. R. W. Johnson, commanding Second Division; Brig. Gen. Jeff. C. Davis, commanding First Division of the Twentieth Corps, my thanks are due for their earnest co-operation and devotion to duty.
       Major-General Sheridan is commended to his country. Brigadier-Generals Johnson and Davis are commended to their country, and recommended to my superiors for promotion.
       Brig. Gen. August Willich, commanding First Brigade, Second Division, and Col. W. W. Berry, Fifth Kentucky Volunteers, commanding Third Brigade, are strongly recommended by General Johnson for promotion.
       Col. L. P. Bradley, Fifty-first Illinois, commanding Third Brigade, of Third Division, and Col. Bernard Laiboldt, Second Missouri Volunteers, commanding Second Brigade, Third Division, are strongly recommended for promotion by General Sheridan.
       It affords me pleasure to add my testimony as to the gallantry of these distinguished soldiers, and commend them to my superiors for promotion.
       The Twentieth Army Corps, during the two days' battle, lost five pieces of artillery and captured seven from the enemy, also retaking the Eighth Indiana Battery lost on Saturday.
       Two guns lost by Johnson's division were so disabled by shot and the killing of horses that it was impossible to remove them.
       Davis' division did not lose a gun or wagon during the conflict.
       To my staff, Lieut. Col. G. P. Thruston, assistant adjutant-general and chief of staff; Maj. Caleb Bates, aide-de-camp; Capt. B. D. Williams, aide-de-camp; Capt. F. J. Jones, aide-de-camp; Capt. J. H. Fisher, volunteer aide-de-camp; Lieut. Col. H. N. Fisher, assistant inspector-general; Lieut. Col. J. F. Boyd, quartermaster; Lieut. Col. G. W. Burton, commissary of subsistence; Maj. G. A. Kensel, chief of artillery; Capt. A. C. McClurg, acting assistant adjutant-general and ordnance officer; Capt. I. C. McElfatrick, topographical engineer; Surg. J. Perkins, medical director; Capt. A. T. Snodgrass, provost-marshal, my thanks are due for their devotion to duty, gallantry in action, and intelligence on the field.
       Throughout the entire campaign, since the corps left Stevenson, the Thirty-ninth Indiana Mounted Infantry, under its efficient commander, Col. T. J. Harrison, has performed the most arduous and important service. On the morning of September 20, when the enemy was endeavoring to turn our extreme right, this fine regiment made a most gallant charge, driving the enemy several hundred yards and inflicting terrible punishment upon them.
       The brigade of Colonel Wilder charged the rebel lines at the same time very handsomely, capturing nearly 200 prisoners.
       I desire also to speak in terms of the highest commendation of the conduct of my escort from the Second Kentucky Cavalry, commanded by Lieutenant Batman, and of the provost guard attached to corps headquarters, and under command of Captain Richards, of the Eighty-first Indiana Volunteers.
       The signal corps, under Lieut. B. R. Wood, jr., has also been useful and efficient during the entire campaign.
       For particular instances of individual bravery I refer you to the inclosed reports of division and brigade commanders.
       A list of killed and wounded and missing will be forwarded as soon as it is completed.

All of which is respectfully submitted.
Maj. Gen. of Vols., Comdg. Twentieth Army Corps.