After the battle of Antietam in September of 1862, President Lincoln replaced Gen. George McClellan with Gen. Ambrose Burnside. Burnside marched the Army of the Potomac south to the Rappahannock River opposite the town of Fredericksburg. He hoped to use pontoons to cross the river before the Confederates caught up, so he could advance on Richmond. But a delay of the pontoons forced the army to halt and wait.

Meanwhile, the Confederates reached Fredericksburg, across the river. Gen. James Longstreet’s corps took position behind a stone wall on Marye’s Heights, a ridge near the town. Gen. “Stonewall” Jackson’s corps formed on Longstreet’s right.

Burnside determined to break through the Confederate line, then turn and smash the two sections, destroying the Confederate army. Several of his generals disagreed, arguing that such an attack would fail because the Confederates had a strong position with open fields in front of them, leaving the Union attackers unprotected from enemy fire as they advanced. Burnside remained unmoved. After the meeting where he outlined his plan, he asked Col. Rush Hawkins, a brigade commander, what he thought. Hawkins replied, “If you make the attack as contemplated it will be the greatest slaughter of the war; there isn’t infantry enough in our whole army to carry those heights if they are well defended.”

Two days later, on December 13, Burnside attacked anyway. The Union lines advanced across the fields into a hail of Confederate bullets and shells coming from troops solidly entrenched behind the stone wall. One single shell killed or wounded 18 men in the Irish Brigade. Several times, the Union troops stopped under this withering fire to tear down fences that blocked their way. They continued to within 25 yards of the Confederates before the overwhelming fusillade stopped them. Units became intermingled as more and more men fell. Again and again the Union soldiers threw themselves against the Confederate line. Fourteen charges were made, and each one failed.

In an attempt to escape the Confederate fire, many soldiers hid in small ravines or lay down behind dead horses. Many did not even try to fire at the Confederates. One bullet would cause the whole Confederate line to return fire. Some men loaded their rifles, then jumped up, fired, and fell as quickly as they could to avoid being shot. But soon the Confederates learned to watch for them in order to shoot them as soon as they rose.

On the Union left, several regiments managed to break the Confederate line. They held their positions for about an hour, until lack of ammunition forced them to retreat.

Finally, night fell, but it did not bring an end to the death and suffering. Some men tried to escape across the pontoon bridges in the darkness, but many could not leave the field. As the night dragged on, many men died from their wounds or froze to death. In all, the Union army lost over 12,500 killed, wounded, or missing at Fredericksburg. The Confederates lost a little over 5,000.