In February 1862 a Union army-navy offensive succeeded in capturing Fort Henry and Fort Donelson, located respectively on the Tennessee and Cumberland Rivers, near the Tennessee-Kentucky border, and the fall of the two forts initiated a series of Union triumphs that left the Confederacy struggling for life. The Confederate defensive line across southern Kentucky immediately collapsed, and the southern forces retreated from northern Tennessee to Alabama and Mississippi. Major General Don Carlos Buell’s Federal forces occupied Nashville, a major arsenal, transportation center, and supply depot, and the city suddenly found itself the first Confederate state capital to fall to the enemy.
The capture of Fort Henry opened the Tennessee River to Federal penetration to the Alabama and Mississippi state lines. Forces under Major General Ulysses S. Grant advanced south to Pittsburg Landing, located on the west bank of the Tennessee River, about twenty miles north of Corinth, Mississippi. That put Union forces dangerously close to the Confederacy’s most important east-west railroad, the Memphis and Charleston line, which made a junction at Corinth with the north-south Mobile and Ohio. If the Union army, designated the Army of the Tennessee, captured Corinth, not only would the Federals control the railroad, but Memphis would likely fall and open several hundred miles of the Mississippi River to Union forces. By late March, Major General Henry W. Halleck ordered Buell and his Army of the Ohio to join Grant for an offensive against Corinth.
Meanwhile, the Confederates concentrated their forces at Corinth in order to stop the Union advance before Buell could reinforce Grant. Their effort culminated in the battle of Shiloh, named for the Shiloh Methodist Church, located near the Union encampment. The Confederate commander, General Albert Sidney Johnston, marshaled about forty-four thousand troops for his Army of Mississippi; General P. G. T. Beauregard was second-in-command. Johnston’s army moved out of Corinth on April 3, hoping to mount a surprise attack on Grant’s forty-two thousand men before Buell’s twenty-five thousand troops arrived from Nashville. The intended one-day march became a three-day trek, however, as rain, complicated marching orders, rugged terrain, and inexperienced soldiers slowed the timetable. Beauregard wanted to call off the offensive, believing that the noise of the troop movement had alerted the enemy, now firmly entrenched. But Johnston refused to turn back and ordered the attack for Sunday, April 6.
The first fighting occurred as Southern skirmishers, preceding their battle lines, engaged Union patrols at about five o’clock in the morning. The Northern soldiers fought a delaying action but fell back as the main body of Confederates moved forward. Despite the action in the woods, many Union soldiers remained unaware of the danger and went about their usual Sunday morning camp routines. Suddenly, yelling Confederates poured out of the woods to the south, and in some sectors, right into the Union camps. For the next two days, one hundred thousand Union and Confederate soldiers fought along the banks of the Tennessee River.
At first, a Confederate victory seemed likely, as the Federal encampments lacked tactical formation, and green troops manned the advanced positions. Neither Grant, at his headquarters nine miles away, nor Brigadier General William T. Sherman, the camp commander, expected an attack. The Southerners benefited from the elements of surprise and momentum, as well as a numerical advantage. Union mishaps compounded the Southern advantage; the Federal division of Major General Lew Wallace never got into the April 6 fight, and some five thousand Union soldiers fled in panic.
Nevertheless, the Southern attack did not develop as originally planned by Johnston. An inefficient attack formation and confusion over whether to drive the enemy back to Pittsburg Landing or away from it slowed the Confederate momentum. The Southern army lost command control as regiments, brigades, divisions, and corps became hopelessly intermingled. In mid-afternoon, Johnston sustained a leg wound and bled to death shortly thereafter. Perhaps most importantly, a natural defensive position, “the Hornets’ Nest” as it was dubbed by the Southerners, became a rallying point for Federal troops, as they fell back toward the Landing. Troops from several divisions joined the men from Brigadier General Benjamin F. Prentiss’s division in defending the position against an aggressive Southern attack. The action at the Hornets’ Nest cost the Confederates too much time and too many men and focused their attention away from an opportunity to break through the weaker Union left nearer the river. The delay awarded Grant, who hurried from Savannah at the sound of the battle, a desperately needed chance to establish a last line of defense at Pittsburg Landing.
Beauregard, in command after Johnston’s death, chose not to make an attack on the Federal position at the Landing. Buell arrived with reinforcements during the night, and Lew Wallace came up from Crump’s Landing to take a position on the right side of the Union line. In all, the Federals mustered an additional twenty-five thousand men on April 7. They drove the Southerners back across the battlefield and forced them to retreat to Corinth.
The two-day carnage approached twenty-four thousand casualties; each side counted more than seventeen hundred dead and eight thousand wounded in addition to the missing. With casualties totaling nearly five times those of First Bull Run, Shiloh became the bloodiest battle of the war up to that time. Both sides recognized the struggle as one of the most important in the war, as the Union army had turned back a major Southern counteroffensive. With the arrival of reinforcements, a powerful Union army held its position on the flank of the line of the Mississippi within a few miles of the strategic Memphis and Charleston Railroad. The battle opened the way to a split in the Southern forces along the Mississippi and doomed the western Confederacy.
Larry Daniel, Shiloh (1996); James L. McDonough, Shiloh: In Hell before Night (1977)