The information Halleck collected at Washington indicated that Longstreet's column was a strong one, possibly numbering 40,000, but he urged that Burnside should not retreat. [Footnote: Id., p. 145.] The National forces in East Tennessee consisted, first, of the troops under General Willcox at Cumberland Gap and the vicinity, 4400; the Ninth Corps, Brigadier-General Potter commanding, 6350; and part of the Twenty-third Corps, 7800, with two bodies of cavalry numbering 7400. [Footnote: Official Records, vol. xxxi. pt. i. p. 811.] Willcox's troops and part of the cavalry were ordered to hold in check the Confederates under Ransom, one brigade of cavalry under Colonel Byrd was posted at Kingston to keep up communication with Chattanooga, and the rest was available to meet Longstreet, either in the field or behind intrenchments at Knoxville, as Grant should direct.
Longstreet's army was considerably overrated in the information received from Washington, but not unnaturally. [Footnote: Halleck to Grant, Id., pt. iii. p. 145.] It was assumed that he had with him all three divisions of his corps, and it was not known that Walker's division was detached. It had also been known that Stevenson's division was at Sweetwater two or three weeks before Longstreet assembled his forces there, and it seemed certain that it was the advance-guard of his whole command. Indeed Longstreet himself supposed so, and complained because it was not allowed to remain with him. [Footnote: Id., p. 635.] Concluding, therefore, that Burnside could not safely meet Longstreet in the field, Grant proposed that he should hold the Confederates in check, retreating slowly. He believed that in a week from the time Longstreet showed himself at the Holston River, he could assume the aggressive against Bragg so vigorously as to bring Longstreet back at speed and relieve Burnside of the pressure. [Footnote:Id., p. 143; to Halleck, p. 154.] Bragg also expected this, and had ordered that the railway connection should be maintained as far as possible, looking for a crushing blow at Burnside and a quick reassembling of his forces. The delays between the 4th and 14th of November had been fatal to this plan, and it would have been the part of wisdom to abandon it frankly.
Neither the authorities at Washington nor Grant gave Burnside credit, at first, for the cheerful courage with which he was ready to take the losing side of the game, if need be, and thus give a glorious opportunity to the co-operating army. His chivalrous self-forgetfulness in such matters was perfect, when it was likely to lead to the success of the larger cause he had at heart. To reach a more perfect understanding than could be had by correspondence Grant sent Colonel J. H. Wilson of his staff to Knoxville to consult personally with Burnside. This officer was accompanied by Mr. Dana, and their dispatches to Grant and to the Secretary of War give a clear and vivid picture of the situation. [Footnote: Official Records, vol. xxxi. pt. i. pp. 258, etc; pt. iii. pp. 146, 154.] Burnside clearly saw the importance of making his stand at Knoxville, and proposed to fortify that place so that he could stand a siege there. [Footnote: Burnside to Willcox, Id., p. 177. B.'s Report, Id., pt. i. p. 273.] He proposed to draw back slowly from the Holston at Loudon, tolling Longstreet on and getting him beyond supporting distance of Bragg. When Grant should have disposed of the weakened enemy in his front, he could easily drive Longstreet out of East Tennessee into Virginia. Grant approved without qualification the course taken by Burnside. [Footnote: Grant to Burnside, Id., pt. iii. p. 177.] During the siege which followed, there was a good deal of solicitude about Burnside, but it should be remembered in justice to him that his own confidence never faltered and was fully justified by the result.
Prior to the visit of Wilson and Dana he had sent his engineer, Captain O. M. Poe, to Loudon to remove the pontoon bridge before the occupation of the south bank of the Holston by the enemy should make it impossible to save it. The bridge had been made of unusually large and heavy boats, and it was a difficult task to haul them out of the water and drag them half a mile to the railway. The south end of the bridge was loosened and the whole swung with the current against the right bank, where the dismantling and removal of the boats was successfully accomplished under the eyes of a cavalry force of the enemy which watched the performance from the opposite bank. The bridge was carried to Knoxville and laid across the Holston there. Its size and weight proved to be great points in its favor for the special use there, and it was of inestimable value during the partial investment of the town. [Footnote: Poe's Report, Official Records, vol. xxxi. pt. i. p. 294. Century War Book, vol. iii.]
On the 13th of November Longstreet brought up his own pontoons and laid a bridge near Loudon, and the next day began a vigorous advance upon Knoxville. Burnside had matured his plans, and opposed the advance of Longstreet with one division, Hartranft's of the Ninth Corps, and another, White's of the Twenty-third Corps. He was weak in cavalry, however, and could only meet Wheeler's corps with a single division under Brigadier-General Sanders. Burnside had secured Sanders's promotion from Mr. Stanton when the Secretary was at Louisville in October, in recognition of the ability and gallantry shown in the expedition to East Tennessee in June and his other services during the campaign. By giving Shackelford charge of the cavalry operating in the upper valley and putting Sanders in command of those resisting Wheeler, Burnside was sure of vigor and courage in the leadership of both divisions. Longstreet kept Wheeler on the left bank of the Holston, directing him to overwhelm Sanders and move directly opposite Knoxville, taking the city by a surprise if possible. But Sanders opposed a stubborn resistance, falling back deliberately, and held the hills south of Knoxville near the river. Wheeler was thus baffled, and returned to Longstreet on the 17th of November. The absence of his cavalry had been a mistake, as it turned out; for the Confederate infantry, after crossing at Loudon to the right bank, had not been able to push Burnside back as fast as Bragg's plans required, nor had they succeeded at all in getting in the rear of the National forces.
As soon as it was definitely known at Knoxville that Longstreet was over the Holston, Burnside went to the front at Lenoir's to take command in person. [Footnote: Burnside's Report, Official Records, vol. xxxi. pt. i. p. 273.] He left General Parke as chief of staff in general charge of affairs at headquarters, with Captain Poe in charge of the engineer work of preparing lines of defence connecting the forts already planned and partly constructed. Wilson and Dana stayed in Knoxville till the 15th, and then rode rapidly to the westward, passing around Longstreet's columns and rejoining Grant at Chattanooga on the night of the 17th, with latest assurances from Burnside that he would hold Knoxville stubbornly. Longstreet's tactics were to move one of his infantry divisions directly at Burnside's position, while with the other he turned its flank and sought to get to the rear. Burnside met the plan by the analogous one of alternate withdrawals of a division, one holding the enemy at bay while the other took post in echelon in the rear and opposed the flanking column till a concentration could be made.
At Campbell's Station Longstreet attacked with vigor, determined to finish matters with the force before him. Ferrero's division of the Ninth Corps had now joined. Hartranft repulsed an attack by McLaws, whilst the trains and the division of Ferrero passed on, and Ferrero took a strong position half a mile in rear covering the junction of roads. White then retired and came into line on Ferrero's left. When these were solidly in place Hartranft took an opportune moment to withdraw and came into line on the left of White. The manoeuvres were perfectly performed, and the fighting of our troops had been everything that could be desired, meeting and matching Longstreet's veterans in a way to establish the soldierly reputation of all. The comparatively new organization of the Twenty-third Corps proved itself equal to the best, and Burnside declared that he could desire no better soldiers. The same tactics were continued through the day, and Burnside followed the hard labor and the fighting of the day with a night march which brought him to Knoxville on the morning of the 17th. [Footnote: Official Records, vol. xxxi. pt. i. pp. 274, 275, 296.] He had personally handled his little army through the day with coolness and success, and had raised to enthusiasm the confidence and devotion of his men. Each side had a casualty list of about 300.
Wheeler had marched back along the left bank of the Holston half-way to Lenoir's and crossed at Louisville, joining Longstreet again near Knoxville on the 17th, as has been already stated. He now took the advance and pressed sharply in upon the town. General Sanders had been recalled by Burnside from the south, and entering Knoxville by the pontoon bridge, passed out to the westward on the Loudon road, meeting the enemy as he advanced, and gradually falling back to a position a mile beyond the lines, where he made a stubborn stand and held Wheeler at bay till night closed the combat. From the fortified points about the city the cavalry engagement had been in full view, and the heroism of Sanders and his men was in the presence of a cloud of witnesses. They made little barricades of rail piles, and though these were frequently sent flying by the cannon balls and shells with which Alexander's artillery pounded them all day, they held at nightfall the line Sanders had been directed to hold in the morning, and had not given back an inch. [Footnote: Colonel O. M. Poe, in "Century War Book," vol. iii. p. 737.]
Knoxville was so situated that its outline was a sort of parallelogram of high ground, averaging a hundred and fifty feet or more above the river which ran along the town on the south. Two creeks ran through the town in little valleys, and in the northern suburbs where the land was much lower than the town it had been practicable, by damming these streams to make inundations which covered a considerable part of the northern front and added very materially to the defences. At the four corners of the parallelogram, enclosed works had been planned for use by a small garrison, and these had been partly constructed. Captain Poe, the chief engineer, had staked out infantry lines connecting these forts, with epaulements for artillery at intervals, and work had been hastened during the days from the 13th of November, as soon as Burnside's plan of holding the city had been approved. When the troops approached the city on the morning of the 17th, the position for every brigade and every battery had been assigned, and officers were in waiting to lead each to its place. All the infantry was put in line except Reilly's brigade of the Twenty-third Corps, which was placed in reserve in the streets of the town. [Footnote: Poe's Report, Official Records, vol. xxxi. pt. i. p. 295.]
The most important of the forts was at the northwest angle of the works, upon a commanding hill. It was afterward called Fort Sanders in honor of the cavalry commander who lost his life in front of its western face. This work was planned as approximately a square with sides of about a hundred yards and bastions at the corners. The eastern front had not been completed, and was now left entirely open, as the northern face connected with the infantry trench. The ditch was twelve feet wide and about eight deep, and the parapet was about twelve feet high, making its crest about twenty feet above the bottom of the ditch. The berme usually left between the bottom of the parapet slope and the ditch was cut away so as to leave no level standing-place at the top of the scarp. This was the work which Longstreet afterward assaulted. Its chief defect was due to the situation and the contour of the ground around, which made its position so prominent a salient in the lines that the flanking fire was necessarily imperfect, leaving a considerable sector without fire beyond the angle of the northwest bastion. The point of the bastion was truncated, and a single gun put in the pan coupé. The three other forts were less elaborate but of similar profile.