Why was it taking so long for Burnside to attack the Confederates at Fredericksburg? Burnside initially wanted to ford the Rappahannock at Skinker’s Neck, ten miles beyond Lee’s right flank, and march directly on the railroad in the Confederate rear. That would force a retreating Lee to protect his supply lines. However, the Union balloon corps reported that Lee had moved sufficient troops to cover his right flank, which stalemated Burnside’s intentions.
Reluctantly, Burnside concluded that he had no alternative but to cross at Fredericksburg, using the town as cover. If he successfully assaulted Fredericksburg, the Confederate troops at Skinker’s Neck would be too far away to prevent Lee’s destruction. So Burnside opted to frontally assault Lee whose army held a strategic, defensive position on the foothills surrounding Fredericksburg.