The Fredericksburg Campaign

(Wikipedia) ... The Union Army began marching on November 15, [1862] and the first elements arrived in Falmouth on November 17. Burnside's plan quickly went awry—he had ordered pontoon bridges to be sent to the front and assembled for his quick crossing of the Rappahannock, but because of administrative bungling, the bridges had not preceded the army. As Maj. Gen. Edwin V. Sumner arrived, he strongly urged an immediate crossing of the river to scatter the token Confederate force of 500 men in the town and occupying the commanding heights to the west. Burnside became anxious, concerned that the increasing autumn rains would make the fording points unusable and that Sumner might be cut off and destroyed. He squandered his initiative and ordered Sumner to wait in Falmouth.
Lee at first anticipated that Burnside would beat him across the Rappahannock and that to protect Richmond, he would assume the next defensible position to the south, the North Anna River. But when he saw how slowly Burnside was moving (and Confederate President Jefferson Davis expressed reservations about planning for a battle so close to Richmond), he directed all of his army toward Fredericksburg. By November 23, all of Longstreet's corps had arrived and Lee placed them on the ridge known as Marye's Heights to the west of town, with Anderson's division on the far left, McLaws's directly behind the town, and Pickett's and Hood's to the right. He sent for Jackson on November 26, but his Second Corps commander had anticipated the need and began forced-marching his troops from Winchester on November 22, covering as many as 20 miles a day. Jackson arrived at Lee's headquarters on November 29 and his divisions were deployed to prevent Burnside crossing downstream from Fredericksburg: D.H. Hill's division moved to Port Royal, 18 miles down river; Early's 12 miles down river at Skinker's Neck; A.P. Hill's at Thomas Yerby's house, "Belvoir", about 6 miles southeast of town; and Taliaferro's along the RF&P Railroad, 4 miles south at Guinea Station.
The boats and equipment for a single pontoon bridge arrived at Falmouth on November 25, much too late to enable the Army of the Potomac to cross the river without opposition. Burnside still had an opportunity, however, because by then he was facing only half of Lee's army, not yet dug in, and if he acted quickly, he might have been able to attack Longstreet and defeat him before Jackson arrived. Continued

Map by Hal Jespersen, www.posix.com/CW