McClernand's division, preceded by the Fourth Illinois cavalry, marched in advance on both roads. No opposition was encountered before reaching the pickets in front of Donelson. The advance came in sight of the fort about noon. McArthur's brigade, forming the rear of the column, halted about three miles from the fort at 6 P.M., and moved into position at half-past ten. It was observed by Colonel W.H. L. Wallace, whose brigade was at the head of the column on the telegraph or direct road between Forts Henry and Donelson, that the enemy's camps were on the other side of the creek, which, on examination, was found to be impassable. He moved up the creek and joined Colonel Oglesby, whose brigade was the advance on the Ridge road, in a wooded hollow, screened from view from the works by an intervening ridge.

The moment that deployment was begun, Oglesby's brigade, which was the farther to the right, was briskly attacked by cavalry, who, after a sharp skirmish, retired. McClernand's division was assigned to the right, C.F. Smith's to the left. The day was spent feeling through the thick woods and along deep ravines, and high, narrow winding ridges. At times a distant glimpse was caught, through some opening, of the gleam of tents crowning a height; at times, a regiment tearing its way through blinding undergrowth was startled and cut by the sudden discharge from a battery almost overhead, which it had come upon unawares. The advancing skirmish-line was in constant desultory conflict with the posted picket-line. Batteries, occasionally, where an opening through the timber permitted, took a temporary position and engaged the hostile batteries. The afternoon passed in thus developing the fire of the line of works, feeling towards a position and acquiring an idea of the formation of the ground. Smith's division, by night, was in line in front of Buckner, and McClernand's right had crossed Indian Creek and reached the Wynn's Creek road. The column had marched without transportation. The men had nothing but what they carried in knapsack and haversack. Shelter-tents had not yet come into use. The danger of drawing the enemy's fire prevented the lighting of camp-fires. The army bivouacked in line of battle. The besieged resumed at night their task, which had been interrupted by the afternoon skirmishing, of completing and strengthening their works.

Next morning, Thursday the 13th, arrived, and the fleet had not come. Fifteen thousand men, without supplies, confronted 20,000 well intrenched. A party was sent to destroy the railroad bridge over the Tennessee, above Fort Henry, the trestle approach to which had been partly destroyed by Lieutenant-Commander Phelps, to prevent effectually reinforcements reaching Donelson from Columbus. Order was sent to General Lewis Wallace, who had been left with a brigade in command at Fort Henry, to join the besieging force. The two divisions on the ground prosecuted the work of feeling for position and probing the enemy. Colonel Lauman's brigade, of C.F. Smith's division, bivouacked the night of the 12th, about a mile from the intrenchments. On the 13th he moved over the intervening ridges till he came in view of the portion of the works held by Colonel Hanson, constituting the right of General Buckner's line. A deep hollow filled with timber filled the space between Lauman and the works before him. On the farther slope, crowned by the works, the slashed timber made an extensive abattis. Colonel Veatch, with the Twenty-fifth Indiana, advanced across the ravine or hollow, and forced his way partly up the slope. He remained with his command two hours exposed to a fire to which, from their position, they could make no effectual reply, and were recalled. The Seventh and Fourteenth Iowa moved up to the left of the position reached by Colonel Veatch, and a detachment of sharpshooters was posted so as to reach with their fire the men in the trenches and divert their fire. At night Lauman withdrew his command to the place of the previous night's bivouac. Colonel Cook's brigade advanced, the morning of the 13th, on the right of Lauman's. The left of his line came also in front of Hanson's works. The valley was here filled with such an "immensity of abattis" that he did not feel justified in ordering an attempt to cross it, but kept up through the day a desultory fire of skirmishers and sharpshooters over it. The demonstration made by Lauman and Cook appeared so threatening that General Buckner sent the Eighteenth Tennessee to reinforce Hanson. The Seventh Illinois, which constituted the right of Cook's advance moving through the timber where a ridge leads to a battery at a salient in General Buckner's line, suddenly found itself under fire and retired. Colonel Cook formed his line with the other four regiments upon a ridge overlooking the enemy's intrenchments, about six hundred yards from them, separated from them by a valley dense with timber, mostly cut so as to form abattis, and remained in this position for the night.

McClernand continued pressing all day to his right, following the course of the ridge along which the Wynn's Ferry road passes. By night his right nearly or quite reached the point where the Wynn's Ferry road issued from the intrenchments. His artillery was very active; the companies acting at times separately, at times uniting and concentrating their fire on some well-served battery, they silenced temporarily several batteries, and in the afternoon shelled some camps. A determined assault was made on the position held by Maney's battery, supported by Colonel Heiman with the Tenth, Forty-eighth, and Fifty-third Tennessee, and the Twenty-seventh Alabama. This position was, at the same time, the most salient and the most elevated in the entire line of intrenchment. It was so traced that both faces were swept by artillery and infantry fire from portions of the works to the right and the left. Colonel Morrison was directed with his brigade, the Seventeenth and Forty-ninth Illinois, to assault this position. Colonel Haynie, of the Forty-eighth Illinois, senior to Morrison, was ordered to join him and take the command. Morrison, on the right, assaulted the left face of the work; the Seventeenth and Twenty-fifth assaulted the right. Crossing the valley, they began the ascent, encountered the tangled abattis, and while striving to tear their way through it, under a plunging fire from the battery and the infantry above them, they were assailed by artillery and infantry from a long extent of line beyond. They recoiled from this toil and this double fire. The Forty-fifth Illinois was sent to reinforce Morrison. The four regiments started again, forced their way still farther up the abattis, and were again repelled. Undaunted, they rushed up the hill-side the third time. Part of the command pierced through the abattis and reached the rifle-pits. The summit of the rifle-pits was a blaze of musketry. Maney's guns hurled shrapnel into their faces. To Morrison's right and to Haynie's left, the long line of rifle-pits was a line of musketry, and from projecting points the batteries sent their fire. Morrison was wounded. His men could not climb over the intrenchment. The regiments recalled, fell back in order out of fire. The dead leaves on the hill-side were inflamed in some way, in this close contest, and when artillery and musketry had ceased, helpless wounded lying on the hill-side were burned to death. Colonel Heiman's men, leaping over their works, were able to save some. General Buckner reported his loss in the assault on Hanson's position as thirty-nine killed and wounded. Ten killed and thirty wounded were reported as Heiman's loss, most of them in Maney's battery. Nearly every regiment in the entire line of the intrenchments suffered some casualties from the National artillery. The national loss was more severe. The pertinacity of the attack through the day prevented the besieged from suspecting the inferiority in numbers of the attacking force.

The Carondelet, a thirteen-gun ironclad, arrived in the morning of the 13th, and fired at the water-batteries at long-range. One shot struck a thirty-two-pound gun, disabling it, and killed Captain Dixon, of the engineers, who had assisted Colonel Gilmer in the construction of both Henry and Donelson. A shot from the one hundred and twenty-eight-pound gun in the upper battery, entering a porthole, damaged the machinery of the Carondelet, and she drew out of range.

The fleet, together with transports bringing reinforcements and supplies, arrived toward evening. McClernand had moved so far around to the right as to leave a wide gap between his left and Smith's division. McArthur's brigade, of Smith's division, was moved to the right. Near midnight, upon the request of General McClernand, McArthur detached two regiments and moved them farther to the right, to within a quarter of a mile of McClernand's left. Severe wind set in with the night. Snow fell and the ground froze. Fires could not be lighted by either army. Some of McClernand's regiments, having thrown away their blankets on going into action, sat up all night.

General Lewis Wallace arrived from Fort Henry about noon, Friday, the 14th, and was placed in command of a division of troops just arrived on the transports, styled Third Division. The First Brigade, commanded by Colonel Charles Cruft, consisted of the Seventeenth and Twenty-fifth Kentucky, and the Thirty-first and Forty-fourth Indiana. The Third Brigade, commanded by Colonel John M. Thayer, comprised the Fifty-eighth and Seventy-sixth Ohio, and the First Nebraska. The Second Brigade was not organized; but in the course of Saturday, the Forty-sixth, Fifty-seventh, and Fifty-eighth Illinois and Twentieth Ohio, reported separately, and were assigned to duty. General Wallace moved into position on the right of General C.F. Smith, so as to hold the narrow ridge or spur which faced the right of Buckner's line, and was separated from McClernand by the valley of Indian Creek.

The day was quiet along the National lines, and was spent in defining and adjusting the commands in position. Skirmishers exchanged occasional shots, and artillerists from time to time tried the range of their guns. McClernand moved his right still nearer to the river, Oglesby's brigade reaching nearly to the extreme left of the Confederate works, and to the head of the back-water up the valley of the small brooks above Dover; the Eighth, Eighteenth, and Twenty-ninth Illinois were respectively posted across the three roads, which, leaving the main road along the ridge, called Wynn's Ferry road, crossed the hollow and through the enemy's intrenchments into Dover. The cavalry reconnoitered around the enemy's left, to the muddy and overflowed bottom extending back from the river immediately above Dover.

According to the report of General Buckner it was decided, in a council of general officers held that morning, to cut a way for the garrison out through the enclosing force at once, before delay would make it impracticable; that General Pillow was to lead, and Buckner to cover the retreat of the army if the sortie proved successful. Buckner made the necessary preparations, but early in the afternoon the order was countermanded by General Floyd, at the instance of General Pillow, who, after drawing out his troops for the attack, thought it too late for the attempt. Though this is not mentioned in the reports of General Floyd, General Pillow, or Colonel Gilmer, Colonel Baldwin in his report says that General Buckner formed his division in open ground to the left and rear of the intrenchments, for the purpose, apparently, of attacking the National right, Colonel Baldwin's command being the head of the column; that the column marched out by a road about two hundred yards from the left of the intrenchments, and approached the right of the National line by a course nearly perpendicular to it; but, after advancing a quarter of a mile, General Pillow said it was too late in the day to accomplish anything, and the troops returned to their quarters. Major Brown, commanding the Twentieth Mississippi, reports substantially the same, and adds they were under fire as soon as they began the advance, and one of his men was shot before they advanced one hundred yards.

About three o'clock in the afternoon Flag Officer Foote moved his fleet up the river to attack the fort. The flag-ship St. Louis and three other ironclads, the Carondelet, Louisville, and Pittsburg, each armed with thirteen guns, advanced, followed by the wooden gunboats Tyler and Conestoga. The water-battery attacked was a mere trench twenty feet wide, sunk in the hill-side. The excavated earth thrown up outside the ditch made a rampart twelve feet through at the summit. Carefully laid sand-bags added to the height of the rampart, and left narrow spaces for embrasures; narrow, but sufficient there, where the channel of the river, straight and narrow, required the fleet to advance in a straight line and with a narrow front. Such a work, at an elevation of thirty feet above the water, was almost unassailable.