First Battle of Bull Run

The First Battle of Manassas, also known as the First Battle of Bull Run, was the first major battle between the armies of the Union of the United States of America and the Confederate States of America. The battle resulted in a decisive victory for the Confederates, highlighting their superior military command at the onset of the war. However, the battle also signaled that either side would not win the war quickly, foreshadowing the bloody conflict. Learn about the outcome of the First Battle of Bull Run and its significance here.

First Battle of Bull Run Location

The First Battle of Bull Run's location was in Virginia, just north of the city of Manassas and only around 30 miles southwest of Washington, DC. In other words, the First Battle of Bull Run's location was nearly right on the borders of the Union and Confederacy.

First Battle of Bull Run or First Manassas?: A Note on Names for the Battle

The First Battle of Bull Run is sometimes called the First Battle of Manassas or First Manassas. During the Civil War, it was common for the Confederates to name battles after nearby towns or railroad junctions. They, therefore, called this the Battle of Manassas.

The Union, meanwhile, commonly named battles after nearby rivers or creeks and called this the Battle of Bull Run after a nearby creek. The National Park on the site uses the Confederate name of Manassas, but it is common to see the battle called by its union name in history books and popular culture.

Background to the First Battle of Bull Run

In July 1861, two months after hostilities began following the attack on Fort Sumter, a Union Army of the United States under the command of Brigadier General Irwin McDowell assembled at Washington, D.C., to protect the US capital.

President Abraham Lincoln ordered McDowell to launch a rapid offensive against the Confederate capital of Richmond, Virginia, hoping to bring a quick end to the war. Though McDowell protested because he felt his troops had insufficient training, Lincoln overruled him because the Confederate forces were similarly untrained.

On July 16, McDowell's army began an advance against an opposing Confederate army under the command of General P.G.T. Beauregard. In response, the Confederate forces pulled back across the river known as Bull Run to a defensive line in front of the critical Manassas railway junction near the town of Manassas, Virginia. Successfully defending this position from the Union attack would protect the approaches to Richmond.

Once aware of the Union army's movement, General Beauregard called for reinforcements from the nearby army under the command of Joseph E. Johnston, positioned in the Shenandoah valley. Opposing Johnston was another Union force under the command of General Robert Patterson.

Fig 3 - Painting depicting the First Battle of Bull Run.

First Battle of Bull Run Summary

The First Battle of Bull Run resulted in a Confederate victory, spoiling hopes for the quick end to the war Lincoln had hoped to achieve.

First Battle of Bull Run Begins

Probing attacks across Bull Run from McDowell's forward units encountered stiff Confederate resistance along the river, encouraging McDowell to rethink the position of his crossing.

Meanwhile, Johnston's army in the Shenandoah Valley to the northwest managed to move away from Patterson's opposing force and make for the railroad so they could join with Beauregard's troops. Boarding trains, Johnston's troops were able to use the railway to reinforce Beauregard's army quickly.

Fig 4 - Some spectators set up picnics to watch the battle, likely not expecting the next 4 years of carnage the war would unleash.

Union Flanking Maneuver at Matthews Hill

On July 21, McDowell began an artillery barrage across Bull Run to cover the crossing of his forward units and occupy the Confederates while he sent two divisions to execute a wide flanking maneuver.

The flanking divisions arrived at Matthews Hill, a position to the west of the main force, and Confederate troops quickly maneuvered to stop the advance.

Forming into battle lines, each side would reinforce their numbers as they repeatedly traded fire. However, an overwhelming number of infantry and cannons from the Union army eventually forced the Confederates to make an ordered retreat to their prominent position on Henry Hill.

McDowell's Flanking Attempt

In this next First Battle of Bull Run map, you can see the Union attempt to flank the Confederate forces once across the river.

Fig 7 - Map of the Battle of Bull Run on July 21.

Confederates Hold at Henry Hill

In the First Battle of Bull Run Map below see the Confederates holding their positions at Henry Hill in the most decisive engagements of the battle.

Union Retreat

In this final First Battle of Manassas map, see the Union retreat in the late afternoon of July 21.

Fig 9 - First Battle of Manassas at 16:00 July 21, 1861, showing the Union retreat.

The Outcome of the First Battle of Bull Run

As Union lines broke, Confederate forces pursued the retreating forces. Though they were exhausted and not well organized, they were able to rout the fleeing Union infantry and take many prisoners.

This final rout ended the battle decisively in favor of the Confederacy. In the evening, General Beauregard called a halt to the pursuit, and some of the scattered Union forces continued to retreat as far back as Washington, D.C.

First Battle of Bull Run Significance

The primary significance of the First Battle of Bull Run was that the battle proved to both sides that they were fighting against a determined enemy and would not be able to achieve a quick and decisive victory in the war. It shattered notions that the war would be over quickly or that one side would defeat the other quickly.

In the Union, spectators who had come to see the battle had expected to see a professional army of the United States crush the relatively untrained rebels, but they were shown that no such great advantage in training or command existed. If anything, the battle revealed the Confederate forces had effective leadership.

Following the defeat, President Lincoln called for more soldiers to join the army and for existing enlistments to be extended. The northern states quickly answered the call, and volunteers arrived in large numbers to bolster the Union's forces and continue the war.

In the Union, spectators who had come to see the battle had expected to see a professional army of the United States crush the relatively untrained rebels, but they were shown that no such great advantage in training or command existed. Following the defeat, President Lincoln called for more soldiers to join the army and for existing enlistments to be extended. The northern states quickly answered the call, and volunteers arrived in large numbers to bolster the Union's forces and continue the war.

At the outset of the battle, the Union had hoped that breaking the Confederate armies and advancing on their capital at Richmond, Virginia, would bring about a fast end to the Civil War. The Confederates hoped that crushing the Union army's advance would discourage the Union from continuing the war and securing their independence from the United States.