On the night of December 10th Burnside called his Grand Division Commanders together to tell them that they would be crossing the Rappahannock the next day. Franklin's Grand Division would be crossing south of the city, while Sumner's would cross into the city. General Hooker would split his command and equally support both the other two's crossing. That was the only set of orders Burnside gave his commanders at this time, stating more information about his plan would be forthcoming. All three Generals wondered what was expected from their commands, not knowing what they were to do after they crossed the river. This was just the start of the confusing orders, from Burnside, that plagued the battle for the next four days.

During the early hours of the morning of December 11th the Union Engineers began their work. The Engineers of the 50th New York were given the job of building the pontoon bridges that would cross over into the city. The 15th Engineers from New York were to build the bridges south of the city for Franklin's crossing. The bridge south of town went up fairly easily. The Confederates had only posted two companies of the 18th Mississippi to harass the engineers as they built their bridges there. These men were quickly driven back by Federal artillery fire, which allowed the Engineers to complete these bridges by 9:30 a.m. on the morning of the 11th. Franklin was told to wait until the other bridges in town were completed before he could cross.

The bridges being constructed in town met all kinds of resistance. General Barksdale, on his tour around his defensive positions, heard the Union men as they began to slip the pontoons into the water. He reported back to Lee that the invasion had started and he would wait until the morning fog had lifted before he would put up a resistance to the Union Engineers. Two cannon shots warned the Confederate Army that the Federals were starting to cross. As the fog lifted Barksdale's men began to pepper the Engineers as they worked, driving them back off the bridges. Each time they would fall back the federal artillery would open up and attempt to drive the Rebels away from the shoreline. This continued through out the morning as the Engineers would go back to work only to be driven back each time. Finally, around 1p.m. General Henry Hunt, Burnside's Chief of Artillery, brought to bear over 100 guns on the town. For two hours the Federal Artillery poured over 5,000 shells into Fredericksburg. The town was heavily damaged and set on fire but the Federals were unable to pry Barksdale's brigade from the town. At one point Barksdale ask Longstreet if he should use some men to help put out the many fires. He was told no, that he needed all his men to keep delaying the Federal crossing. Hunt finally suggested that his artillery was unable to drive the Confederates out and that the Union should attempt to send a landing party over to push the enemy away. Burnside agreed and had volunteers from the Massachusetts 19th and 20th regiments along with the 7th Michigan and 89th New York assigned to make the crossing in the pontoon boats.

The Rebel defenders rained terrific fire upon these boats but all made it across and landed the Union force. Quickly a hard fought battle developed as the Yankees pushed into the town to meet the well placed defenders. The Confederates began to fall back street by street doing harsh damage to the Union troops as they advanced. Around 4:30 p.m. Longstreet gave the orders for Barksdale to fall back out of town. They had accomplished their mission by delaying Sumner's crossing by almost a full day. One Lieutenant, Lane Brandon, refused to fall back when he found out that he was battling a former classmate from Harvard, a Lieutenant Henry Abbott, of the 20th Massachusetts. Brandon had to be arrested and pulled out of town even though his company was fighting hard and had driven back the Massachusetts troops. As the men of Barksdale's brigade fell back out of town and up to the stonewall before Mayre's Heights their Confederate brothers, watching from the heights, cheered them for a job well done. The Union, at last, had their foothold into Fredericksburg.

All along Franklin was waiting before he could cross any troops over the river in the southern section. Around 4:30 p.m. he was allowed to send men across. First to cross was the brigade of General Charles Deven's, along with two regiments of another brigade. Here Burnside changed his mind again and ordered the two regiments back as he wanted only Deven's brigade across to hold the Bridgehead. He would wait until the morning to send the rest of Franklin's troops over. Again, for some reason, Burnside had delayed in pushing his advantage.

Lee didn't wait. During the evening of the 11th he recalled Jackson along with two of his divisions. Both A.P.Hill's division and Jackson's division, under the command of General William Taliaferro arrived and took their place in relief of Hood's division's stretched line. Hood moved his men toward the left while Hill filled his position in line along the woods, connecting with JEB Stuart's cavalry at Hamilton's Crossing. Taliaferro's men were set in support behind Hill.

As the night turned into the dawn of December 12th Lee was expecting Burnside to attack this day. But would he?

December 12th started with Burnside moving most of his men across the pontoon bridges into position on the west side of the Rappahannock. Burnside again was unsure of what action he wanted to take, so the day was wasted with no attacks forth coming from the Federal Army. The delay caused one of the worst acts of the war, the total looting of Fredericksburg. Since the citizens had evacuated and the Rebels had abandoned the town, it was wide open. Fredericksburg was an old Historic town with many beautiful homes filled with fine expensive furnishings. The northern troops went on a rampage destroying the town before them. They smashed glass, mirrors, china and anything breakable. They burned books and paintings, pushed pianos and large pieces of furniture into the streets and burned them in big bon fires. Many of the men took fancy women's clothes and wore them into the streets. General Darius Coach was disturbed by the actions of the men, he placed guards at the pontoon bridges to make sure that the looters did not get their loot across the river into their camps. The total destruction of the town was one of the worst acts of vandalism that occurred at any time during the Civil War. This act was one of the reasons that Lee ordered his army to be on their best behavior when they invaded north after Chancellorsville. He wanted to prevent the same kind of action that the Union soldiers showed at Fredericksburg.

On the Southern end of the field the Corps of General Smith and General Reynolds crossed and set up on the plain between the river and the high grounds held by the Confederates. Smith placed his Corps, anchored on the right at Deep Run Creek running left to the south, while Reynolds placed his Corps on the left flank of Smith bending east and coming to rest on the Rappahannock River. Here Franklin and his Corps commanders waited for orders from Burnside. They felt that they could attack in force and roll up the right flank of the Confederate line. Finally, Burnside rode over late in the afternoon to inspect Franklin's position. Afterwards Franklin and his Generals urged Burnside to approve an all out attack. Burnside again wavered, only leaving the impression that orders for the attack would be forth coming. With that Franklin and his commanders prepared for their attack. But no word came down from Burnside. Franklin was told that his orders were still coming, but none came by the night of the 12th.

While the Yankee troops were looting Fredericksburg and Franklin was sitting back waiting for orders to come from Burnside, Lee was making sound decisions. Early in the afternoon Lee, Jackson and Major Von Borcke, JEB Stuart's chief aide, rode along their lines scouting the federal placements. Lee determined that Burnside had placed the majority of his troops across the river and would not be moving on Port Royal or Skinker's Neck. He ask Jackson to recall both General D.H. Hill and General Jubal Early and place their divisions along Jackson's front. By the morning of December 13th Jackson would have over 30,000 men in a 3,000 yard sector. Late on the night of the 12th Jackson rode his lines with an aide and felt very confident about his position and the up coming battle. So confident that as they rode into their headquarters Jackson's aide claimed that the General began to whistle.

Jackson should have not been confident. There was a 600 yard gap in A.P. Hill's line, right in front of the Union's position. When Hill deployed his division he left a gap nearly one fifth of his total line. The gap was in an area of swamp and tangled underbrush in the woods that formed a triangle toward the railroad. The gap lay between the brigades of General James Lane and General James Archer. Placed behind these two was the brigade of General Maxcy Gregg. Gregg was placed in support and he thought that there were confederate troops in front of his men. This oversight was spotted by General Stuart but he felt that Jackson was aware of the situation and would correct it. For some reason neither Hill nor Jackson saw or reacted to what could have been a fatal mistake. Could the Federals take advantage of Jackson's mistake on the morning of the 13th?

As day broke on December 13th a heavy morning fog laid over the Fredericksburg area. Franklin had yet to hear back from Burnside whether his plan had been approved or not.  At 7:45 a.m. Franklin received his orders from Burnside. They were not the orders that Franklin was prepared to hear. Burnside ordered Franklin to keep his command in position and send out "a division at least" and seize the high grounds around Hamilton's Crossing. This was nothing like what he and Burnside had discussed the afternoon before. Franklin did not know how to interpret these orders. He was unsure how many men he was to use. After reading them many times he decided to send forth one division, Meade's, with Doubleday's and Gibbon's men in support. Months later, at a Congressional hearing, Burnside stated he meant for Franklin to use his whole Grand Division to turn the Confederate flank and capture the heights in the Hamilton's Crossing area. Sumner's attack on Marye's Heights was to keep Longstreet occupied so he couldn't assist Jackson. But Burnside failed to communicate this to his Grand Division Commanders before they went into battle. Again confusion about orders led to bad communication among the high command structure of the Army of the Potomac, giving it little chance to succeed in the battle.

At 8:30 a.m., after recieving their battle orders, Franklin had Reynolds place the division of General Abner Doubleday to the extreme south of the Union line along the Old Richmond Road, facing west towards the area known as Hamilton's Crossing. On the right flank of Doubleday was the division of General George Meade followed to his right by John Gibbon's division. Smith's Corps was then placed along this line to form the right flank of the army on the southern end of the field. Franklin was ready to attack, for he also had in reserve parts of Hooker's Grand Division, and that morning he fielded over 60,000 men. Jackson was also ready to fight. During the night the divisions of D.H. Hill and Ewell, being led by General Early, arrived and were placed in reserve behind General A. P. Hill's division. The confederate line on Jackson's front lined up as follows: In the center of the whole Rebel line was Hood's division, a part of Longstreet's Corps, which if needed was to act under Jacksons command for any emergency. Next was the division of A.P. Hill, which wound around the woods behind the Richmond, Fredericksburg & Potomac Railroad. Placed on the extreme right flank, covering from the end of the woods at Hamilton's Crossing to the Rappahannok River, was JEB Stuart's Cavalry brigade. Behind Hill and part of Stuart were three divisions in reserve; D.H. Hill, Early and Taliaferro. Both armies were set to do battle.

As the Federal's line was placed into position the fog prevented the Confederates from seeing what was before them. All they could do was listen as they heard bands playing, officers shouting and the sound of troops marching into place. All was ready except for the fog that laid heavily on the ground.

Awakening early in the morning Jackson decided to put on his new uniform. His wife had sent him a new hat, Stuart had given him a new jacket which went with new trousers and boots given to him by the people in the Shennandoah Valley. As he left his headquarters to attend a meeting at General Lee's headquarters, he caught the attention of all the soldiers he passed. They all felt it strange to see "old Jack" dressed up. Arriving at Lee's headquarter, Jackson became the talk of all those around. Taking quite a ribbing he finally stated that it was all Stuart's fault. Then Lee and his Generals got down to business. As the fog began to lift they could see the federals massing against Jackson's front. Asked, as he mounted his horse to return to his command, what he was going to do with all those Yankees in front of him, he replied, "give them the Bayonet". And with that off he rode to see that it was done.