Wednesday, December 10, 1862
General Ambrose Burnside ordered a concentration of the army for the following morning in preparation for crossing the Rappahannock River into Fredericksburg. The engineer brigade had finally arrived with the pontoon bridges and had orders to deploy the bridges at three crossing stations along the river: one near the rope-ferry at the upper end of the city; another near the steamboat landing at the lower end of the city; and a third near the mouth of Deep Run a mile south of the second crossing. These three locations would be known respectively as the Upper Pontoon Crossing, the Middle Pontoon Crossing, and the Lower Pontoon Crossing. The Upper Pontoon Crossing had two bridges, while the other two crossings had one bridge each.1
1George A. Bruce, The Twentieth Regiment of Massachusetts Volunteer Infantry 1861 - 1865 (Cambridge, Massachusetts: The Riverside Press, 1906), 190-195.