Battle of Shiloh

Battle of Shiloh: Summary

Despite the loss at Manassas, the Union army in early 1862 was able to achieve several victories in the west, capturing several strategic forts and effectively taking control over the state of Kentucky and much of Tennessee. To continue this trend of successes, Major General Henry Halleck in overall command of the Western Theater ordered Union Brigadier-General Ulysses S. Grant to move down the Tennessee River to take Corinth, Mississippi.

By mid-March, 1862, Grant's army of around 40,000 men had encamped themselves at Pittsburg Landing, Tennessee on the west bank of the Tennessee River, where they organized themselves and prepared to launch an offensive southward. The Confederate Army of Mississippi, under the command of the highly experienced General Albert S. Johnston, chose to attack first, intending to wipe out the Union army before they could begin their offensive.

Battle of Shiloh: Location

In southwest Tennessee, the Battle of Shiloh began in Hardin County. Located along the borders of Mississippi and Alabama, the battle was named after the church by which it was fought, named Shiloh Church.

Fig. 2: Shiloh Church

Battle of Shiloh: Map

The Confederate attack initially hit the western side of the lines along the Union's right flank, engaging with divisions of General William T. Sherman and General John McClernand as seen in the map below. The attack hit hard and the Union forces struggled to hold.

General Grant in overall command moved between the battlefield and Pittsburg Landing to keep his units organized. He arranged for two large groups of reinforcements to join the battle: General Lew Wallace's force (not to be confused with W.H.L. Wallace commanding a division in the Union center) traveling down from the northwest, and another force which was under the command of General Don Carlos Buell arriving from the east across the Tennessee River. The reinforcements however were disorganized by the terrain that you can see on the map below, and in turn, were slow in their arrival.

Fig. 3: Map of the Battle of Shiloh

Battle of Shiloh: Timeline

Early in the morning, around 6:00 AM on April 6, 1862, Confederate forces launched a determined attack against Grant's position. The Union was positioned in a good defensive line, using terrain such as rivers and hills to their advantage, but the soldiers were largely inexperienced and taken by surprise. Though rains had turned some of the roads and pathways to mud, General Johnston ordered the attack to continue.

Around 8:45 AM the Union center, commanded by Generals Prentiss and W.H.L. Wallace, came under attack. Though they repelled the first probing attack against the line, the Union center was overwhelmed and forced back by the Confederate attackers, who quickly seized the Union camps and their supplies.

By 10:30 AM, the western flank under General Sherman was at risk of being overwhelmed, and his and McClernand's forces began to fall back and pivot the overall line toward Pittsburg Landing, forming a wedge. Confederate commander Johnston had hoped to instead make his first progress on the opposite end of the line, to cut the Union forces further west off from Pittsburg Landing.

Fig. 4: Dress of the Confederate army

As the Union pulled back, their lines became shorter and denser, allowing them to hold more effectively against the continued attacks of Confederate infantry, who were slowing in their advance. By noon, Sherman and McClernand had decided on a counterattack, which briefly pushed the Confederates back and forced Johnston to commit his last reserves to the western end of the battle.

On the opposite end of the battlefield, Johnston personally led an attack around 2:00 PM against the Union's eastern left flank, commanded by General Stephen Hurlbut. During the battle, Johnston was shot in the leg, which damaged his artery and killed him around 2:45 PM.

The Hornet's Nest: April 6

In the west, the Union's counterattack had stalled, and Sherman's battered forces were again on the retreat. He and McClernand pulled back further towards Pittsburg Landing. On the opposite end, Johnston's attack had successfully forced the Union's left flank back. They too retreated closer to Pittsburg Landing and began to consolidate a new line with Sherman and McClernand.

The Union retreating forces left the center under Prentiss exposed, and Confederate forces closed in to encircle them. The bloody fighting that followed led their position to be dubbed "Hornet's Nest." Concentrated Confederate artillery hammered the defenders, and though some, including General Prentiss, were able to escape through a gap to the north, General W.H.L. Wallace was killed and over 2,000 Union soldiers were captured as the pocket was closed.

Fig. 5: General W.H.L Wallace

The Evening of April 6

Throughout the late afternoon, Confederate troops advanced up to the Union's new defensive line and continued their attack. The new Union position was potent, however, situated on high ground overlooking a ravine through which the Confederates had to advance under fire, and flanked on one side by the Tennessee River, where Union gunboats provided support with their cannons.

The strength of the Union's new defensive line, as well as stormy weather arriving in the evening, put a halt to the Confederate advance. Confederate forces–now controlled by General P.G.T. Beauregard who had been Johnston's second-in-command–settled into the captured Union camps for the night to regroup.

Beauregard planned to continue the attack and finish off the Union army in the morning.

Fig. 6 General P.G.T Beauregard

Meanwhile, Grant's reinforcements had, at last, arrived, bringing large numbers of fresh troops to the relief of his army. He worked to organize them throughout the night and prepared to launch a counterattack in the morning to destroy the weakened Confederate army.

Union counterattack on April 7

40,000 Union soldiers–among them Lew Wallace and Don Carlos Buell's reinforcing divisions–launched a determined attack against the Confederate camps on the morning of April 7. Though the battered Confederate troops at first managed a defense, throughout the day they were overwhelmed by Grant's superior numbers and broke. By 2:00 PM, General Beauregard ordered a full retreat back to Corinth.

Fig. 7 Newspaper headline on the Battle of Shiloh

Battle of Shiloh: Significance

General Albert S. Johnston's loss was felt in the Confederacy, as he had been one of the most experienced and important generals in the Confederate army. His defeat at Shiloh opened the way for the Union to continue its advance in the west. Corinth would fall under siege during May 1862, and its successful capture by the Union at the end of that month would lead to further opportunities to attack strategic objectives such as Vicksburg in Mississippi.

Battle of Shiloh: Casualties

The Battle of Shiloh saw over 23,000 casualties from both sides combined across the two days of fighting, with around 13,000 on the Union side. This made it the costliest battle of the war up to that point, being significantly deadlier than previous major battles of the Civil War had been. General Ulysses S. Grant, despite his victory, was criticized for the heavy losses he incurred. Though some called for Grant to be sacked, President Abraham Lincoln refused to fire him.