Williamsburg
Not surprisingly, McClellan was unprepared to move on the retreating Confederate Army after they abandoned Yorktown. The bad muddy roads would hamper the retreat almost as much as it would the Union Army. The heaviest rebel guns were left at Yorktown, but not without being "spiked" first.
Spiking a gun meant driving home a metal plug into the ignition hole to detonate the blast which would propel a shot. It was a fast and easy way to make sure a cannon could not be turned around and used in the same battle against the previous owners. Most guns could be saved by drilling the spike out, but care had to be taken so as not to weaken the gun causing it to explode when it was put back into action.
Mcgruder had built quite a few reboudts, earthen fortifications around Williamsburg as a third line of defenses and even a couple of "forts", the largest of which was named Fort Mcgruder. In fact, he may have built too many, as some would lie empty for the Union to take, and then use as a defense against counter attacks.
http://civilwar.org/battlefields/williamsb...amsburgmap.html
By this time, Johnston only wanted to delay the Union advance so he could get his supply trains safely back to Richmond for it's defense, and once again McClellan believed this was where Johnston would stand and fight, just as he mistakenly thought Yorkstown would be the place.
Meanwhile, the two infantry divisions had blundered around the Peninsula, finally getting into position in front of Fort Magruder (the key position in the Confederate lines) early in the morning of 5 May. They were now facing Confederate infantry. The poor roads on the Peninsula slowed the Confederate retreat almost as much as the Union advance, and so James Longstreet (with D.H. Hill), were left to hold the line at Williamsburg while the rest of the Confederate army moved north towards Eltham’s landing, to prevent their being outflanked by Union forcing landing behind them. Early on 5 May, even Hill’s division began to move away.
McClellan was not with the advancing Union troops. He remained at Yorktown, helping General Franklin embark his division ready to attempt that very flanking manoeuvre by sailing up the York River to West Point (or Eltham’s Landing). Instead, General Sumner, his second-in-command, was sent to the front. He reached the front late on 4 May, and ordered Brig.-Gen. William F. Smith’s division to launch a frontal assault on the enemy lines. However, between the Union lines and the Confederate defences was a band of thick woodland, and as darkness fell this first attack had to be abandoned, well before reaching the Confederate lines.
On the next morning the fighting began with a clash between the two lines of skirmishers. For most of the morning the fighting was concentrated in the centre of the line, facing Fort Magruder, and to the south (Union left, Confederate right). Here General Hooker had started with a careful advance, which soon developed into a fierce battle, which was to continue on for most of the day. Both sides soon began to call in reinforcements. On the Confederate side, A.P. Hill was called in before 9.00 a.m., the same time that Kearny was ordered forward on the Union side.
Brig. Gen. Joseph Hooker's 2nd division of the III Corps was the lead infantry in the Union Army advance. They assaulted Fort Magruder and a line of rifle pits and smaller fortifications that extended in an arc south-west from the fort, but were repulsed. Confederate counterattacks, directed by Maj. Gen. James Longstreet, threatened to overwhelm Hooker's division, which had contested the ground alone since the early morning while waiting for the main body of the army to arrive. Hooker had expected Brig. Gen. William F. "Baldy" Smith's 2nd Division of the IV Corps, marching north on the Yorktown Road, to hear the sound of battle and come in on Hooker's right in support. However, Smith had been halted by Sumner more than a mile away from Hooker's position. He had been concerned that the Confederates would leave their fortifications and attack him on the Yorktown Road.
Longstreet's men did leave their fortifications, but they attacked Hooker, not Smith or Sumner. The brigade of Brig. Gen. Cadmus M. Wilcox applied strong pressure to Hooker's line. Regimental bands playing Yankee Doodle slowed the retreating troops as they passed by, allowing them to rally long enough to be aided by the arrival of Brig. Gen. Philip Kearny's 3rd Division of the III Corps at about 2:30 p.m. Kearny ostentatiously rode his horse out in front of his picket lines to reconnoiter and urged his men forward by flashing his saber with his only arm. The Confederates were pushed off the Lee's Mill Road and back into the woods and the abatis of their defensive positions. There, sharp firefights occurred until late in the afternoon.
The crisis came in mid-afternoon. At about noon, Longstreet had become aware that the movement of the rest of the army was so slow that he could fight all afternoon without risking any delay to the move back to Richmond. Accordingly, he launched what he called ‘first grand assault’, which forced the Union lines back from their advanced positions. Despite this success, the Confederate attack eventually faded. The longer the day went on, the more Union troops could be brought onto the field, and Longstreet’s orders were after all only to win a day’s delay for the rest of the army, already moving away to the west. Couch’s and Kearny’s troops arrived in time to prevent any disaster in the centre.
A second fight developed to the north of Fort Magruder. At about 11.00 a.m., Sumner became aware that it might be possible to turn the Confederate left, and dispatched General Winfield S. Hancock to see if it could be done. Hancock faced a potentially difficult task crossing Cub Creek in the face of a Confederate fortification, but for some reason that particular redoubt had been abandoned. At 12 noon Hancock’s men crossed a dam across the stream and occupied the empty redoubt. A second Confederate fort also fell easily into his hands, and Hancock now sent urgent demands for reinforcements to allow him to capture that third fort and secure his advance.
Early split his command, and without first reconoitering, he emerged from the woods not on Hancock's flank, but directly in front of his guns. Early attacked anyway. Early would get a bullet in his shoulder for his efforts. Hancock had been ordered repeatedly by Sumner to withdraw his command back to Cub Creek, but he used the Confederate attack as an excuse to hold his ground. As the 24th Virginia charged, D.H. Hill emerged from the woods leading one of Early's other regiments, the 5th North Carolina. He ordered an attack before realizing the difficulty of his situation—Hancock's 3,400 infantrymen and eight artillery pieces significantly outnumbered the two attacking Confederate regiments, fewer than 1,200 men with no artillery support. He called off the assault after it had begun, but Hancock ordered a counterattack. The North Carolinians suffered 302 casualties, the Virginians 508. Union losses were about 100. After the battle, the counterattack received significant publicity as a major, gallant bayonet charge and McClellan's description of Hancock's "superb" performance gave him the nickname, "Hancock the Superb."
Hancock’s actions were described as brilliant by McClellan. There was a general feeling on the Union side that without Hancock’s successes on the right, the Confederates would not have withdrawn from the Williamsburg line. This was probably not the case, but Hancock’s successful seizure of the Confederate left flank prevented any possibility of a change of plan.
Back at Ft Magruder, at about 2:00 p.m., Brig. Gen. John J. Peck's brigade of Brig. Gen. Darius N. Couch's 1st Division of the IV Corps arrived to support and extend the right of Hooker's line, which had, by this stage, been pushed back from the cleared ground in front of Fort Magruder into the abatis and heavy wood about 600 – 1,000 yards from the Confederate fortifications. The morale of Hooker's troops had been affected terribly by the loss of Captain Charles H. Webber's Battery "H" of the 1st U.S. Light Artillery and Captain Walter M. Bramhall's 6th Battery of the New York Light Artillery. Peck's arrival on the field and his brigade's recovery of Bramhall's battery came at a critical moment for Hooker's division, which was on the verge of retreat.
Two controversies surround this battle. This first is over the nature of the battle itself. Union reports at the time represents it as a victory over a large part of the Confederate army, intent on holding the Williamsburg line just as it had held the Yorktown line. This was not the Confederate’s intention when the fighting started. Longstreet simply needed to delay the Union advance for a day or so to allow the Confederate supply trains to get back into Richmond.
A second controversy developed over the use of primitive landmines – effectively artillery shells rigged to explode as Union soldiers passed. Once again, reports of their use appeared in Union sources soon after the battle. Jefferson Davis even referred to it in his autobiography. However, Joseph Johnston, then the Confederate commander in the field, denied that any such thing had been done. Sadly for his case, the Confederate commander responsible, General G. J. Rains, was an enthusiastic supporter of the idea, and was happy to admit that he had planted four such shells in front of his lines at Williamsburg. Longstreet clearly did not approve, and ordered him to stop.
The fighting at Williamsburg was as intense as any on the Peninsula. Several regiments on the Union side suffered very heavy losses. The Union dead numbered 468, compared to 790 in the two days at Seven Pines or 1,734 during the Seven Days (or 289 for each of the six days of significant battle). This in a battle where only a part of the Union army ever got into action! Reported Confederate losses were not as heavy, although at least one heavily damaged regiment (The 5th North Carolina) did not return a list of casualties.
Both sides could come away from Williamsburg with some satisfaction. Longstreet had held the Union attack off for a day, and allowed the Confederate supply trains to withdraw. In one day’s fighting the Federal’s had pushed the rebels away from a defensive line that appeared to have a similar potential to the lines at Yorktown that had delayed them for a month. McClellan even managed to convince himself that he had been outnumbered at Williamsburg!. The scene was set for the climax of the Peninsula campaign at Richmond.
While many historians called this battale a draw (at the time the North called it a great victory) I think despite the losses, it was a win for Johnston. He made good his retreat, he avoided being flanking by a Union division moving up the York river, and would buy more time to prepare Richmond's defenses. There would be two more minor skirmishes before the Battle of Seven Pines.