At 4:45 am, Thursday, December 11, 1862, Union engineers began constructing five pontoon bridges across the Rappahannock, while under intense fire from a brigade of Mississippi sharpshooters stationed in Fredericksburg. After hours of delay, Burnside ordered his artillery to shell the town in order to silence the Confederate sharpshooters.
Over 5000 Union shells fell on the town, causing widespread destruction, but the Mississippians prevented a crossing by the Federals until well into the afternoon. Even then the Mississippians continued fighting past sundown. When word arrived from the Union balloon corps that Jackson’s troops were still in place some twenty miles downstream from Fredericksburg, a now optimistic Burnside believed that he had caught Lee napping and, with five bridges in place, delayed his assault on Fredericksburg for an additional twenty-four hours.