Battle of Bull Run: Summer of 1861 Disaster for the Union Army

Battle Showed the Civil War Would Not End Quickly or Easily

Illustration of retreat at Bull Run in 1861

Liszt Collection / Heritage Images / Getty Images

The Battle of Bull Run was the first major battle of the American Civil War, and it occurred, in the summer of 1861, when many people believed the war would probably only consist of one big decisive battle.

The battle, which was fought in the heat of a July day in Virginia, had been carefully planned by generals on both the Union and Confederate sides. And when inexperienced troops were called upon to execute the fairly complicated battle plans, the day turned chaotic.

While it looked for a time like the Confederates would lose the battle, a fierce counterattack against the Union Army resulted in a rout. By the end of the day, thousands of demoralized Union troops were streaming back to Washington, D.C., and the battle was generally seen as a disaster for the Union.

And the failure of the Union Army to secure a quick and decisive victory made it clear to Americans on both sides of the conflict that the Civil War would not be the short and simple affair many assumed it would be.

Events Leading to the Battle

After the attack on Fort Sumter in April 1861, President Abraham Lincoln issued a call for 75,000 volunteer troops to come from the states which hadn’t seceded from the Union. The volunteer soldiers enlisted for a term of three months.

Troops began arriving in Washington, D.C. in May 1861 and set up defenses around the city. And in late May portions of northern Virginia (which had seceded from the Union after the attack on Fort Sumter) were invaded by the Union Army.

The Confederacy set up its capital in Richmond, Virginia, about 100 miles from the federal capital city, Washington, D.C. And with northern newspapers trumpeting the slogan “On to Richmond,” it seemed inevitable that a clash would occur somewhere between Richmond and Washington in that first summer of war.

Confederates Massed in Virginia

A Confederate army began massing in the vicinity of Manassas, Virginia, a railroad junction situated between Richmond and Washington. And it became increasingly obvious that the Union Army would be marching south to engage the Confederates.

The timing of precisely when the battle would be fought became a complicated issue. General Irvin McDowell had become the leader of the Union Army, as General Winfield Scott, who had commanded the army, was too old and infirm to command during wartime. And McDowell, a West Point graduate and career soldier who had served in the Mexican War, wanted to wait before committing his inexperienced troops to battle.

President Lincoln saw things differently. He was well aware that the enlistments for the volunteers were only for three months, which meant most of them could be going home before they ever saw the enemy. Lincoln pressed McDowell to attack.

McDowell organized his 35,000 troops, the largest army ever assembled in North America to that time. And in mid-July, he began moving toward Manassas, where 21,000 Confederates had assembled.

The March to Manassas

The Union Army began moving south on July 16, 1861. Progress was slow in the July heat, and the lack of discipline of many of the new troops didn’t help matters.

It took days to reach the area of Manassas, about 25 miles from Washington. It became clear that the anticipated battle would take place on Sunday, July 21, 1861. Stories would often be told about how spectators from Washington, riding in carriages and bringing along picnic baskets, had raced down to the area so they could watch the battle as if it was a sporting event.

The Battle of Bull Run

General McDowell conceived a fairly elaborate plan to attack the Confederate army commanded by his former West Point classmate, General P.G.T. Beauregard. For his part, Beauregard also had a complex plan. In the end, the plans of both generals fell apart, and actions by individual commanders and small units of soldiers determined the outcome.

In the early phase of the battle, the Union Army seemed to be beating the disorganized Confederates, but the rebel army managed to rally. General Thomas J. Jackson’s brigade of Virginians helped turn the tide of the battle, and Jackson that day received the everlasting nickname “Stonewall” Jackson.

Counterattacks by Confederates were helped by fresh troops who arrived by railroad, something entirely new in warfare. And by late afternoon the Union Army was in retreat.

The road back to Washington became a scene of panic, as the frightened civilians who had come out to watch the battle tried to race homeward alongside thousands of demoralized Union troops.

Significance of the Battle of Bull Run

Perhaps the most important lesson from the Battle of Bull Run was that it helped erase the popular notion that the rebellion of the states that allowed enslavement would be a short affair settled with one decisive blow.

As an engagement between two untested and inexperienced armies, the battle itself was marked by countless mistakes. Yet two sides demonstrated that they could put large armies in the field and could fight.

The Union side sustained casualties of about 3,000 killed and wounded, and Confederate losses were about 2,000 killed and wounded. Considering the size of the armies that day, the casualties were not heavy. And casualties of later battles, such as Shiloh and Antietam the following year, would be far heavier.

And while the Battle of Bull Run didn’t really change anything in a tangible sense, as the two armies essentially wound up in the same positions as to where they had started, it was a powerful blow to the pride of the Union. Northern newspapers, which had bellowed for a march into Virginia, actively looked for scapegoats.

In the South, the Battle of Bull Run was considered a great boost to morale. And, as the disorganized Union Army had left behind a number of cannons, rifles, and other supplies, just the acquisition of material was helpful to the Confederate cause.

In an odd twist of history and geography, the two armies would meet about a year later in essentially the same place, and there would be a Second Battle of Bull Run, otherwise known as the Battle of Second Manassas. And the outcome would be the same, the Union Army would be defeated.

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McNamara, Robert. "Battle of Bull Run: Summer of 1861 Disaster for the Union Army." ThoughtCo, Apr. 5, 2023, McNamara, Robert. (2023, April 5). Battle of Bull Run: Summer of 1861 Disaster for the Union Army. Retrieved from McNamara, Robert. "Battle of Bull Run: Summer of 1861 Disaster for the Union Army." ThoughtCo. (accessed June 4, 2023).