Army of the Cumberland
The Army of the Cumberland was one of the Union's principal fighting forces in the Western Theater of the American Civil War. It began life under a different name entirely, raised in November 1861 as the Army of the Ohio under Brigadier General Robert Anderson. What transformed this force into one of the war's most storied armies, and what drove its soldiers to charge up a heavily defended ridge without orders, are questions that cut to the heart of how wars are actually fought.
The army's story moves through some of the most consequential campaigns of the war: a brutal winter battle on the banks of a Tennessee river, a disastrous defeat in a Georgia forest, a siege that nearly starved the army into submission, and a final, decisive rout in the frozen fields outside Nashville. And running through it all is a question of trust between commanders and the men they led.
General Order No. 168, passed on the 24th of October 1862, formally commissioned the XIV Corps into what would become the Army of the Cumberland. That moment marked the transition from the Army of the Ohio, though it took the arrival of Major General William S. Rosecrans to make the change complete. When Rosecrans assumed command of both the army and the Department of the Cumberland, he merged the two entities and gave the combined force its new name.
At the time Rosecrans took over, the army and XIV Corps were essentially the same unit. He organized it into three wings, each led by a senior general: Alexander McCook commanded the right wing, George H. Thomas held the center, and Thomas L. Crittenden led the left. That three-wing structure would not last long. The first significant test under the Cumberland name came at the Battle of Stones River, and afterward the wings were reorganized into three separate corps: the former center became XIV Corps, the right wing became XX Corps, and the left wing became XXI Corps.
Rosecrans proved himself a popular and respected commander as he led the army through the Tullahoma Campaign. He maneuvered his forces with skill, pushing Confederate forces out of central Tennessee without the kind of bloody frontal assaults that defined fighting elsewhere. Then came Chickamauga.
At the Battle of Chickamauga in September 1863, the army suffered a severe defeat. The Confederates drove a large portion of the Union force from the field, and the army retreated to Chattanooga, where Confederate forces promptly laid siege. Rosecrans was unable to break the siege, and his reputation never recovered. On the 19th of October 1863, Ulysses S. Grant arrived at Chattanooga and replaced Rosecrans with George H. Thomas, one of the same wing commanders who had served under him since the army's reorganization. The man who had held the center at Stones River now held command of the entire force.
Grant was skeptical of the Army of the Cumberland heading into the Battles for Chattanooga. He worried their morale had been too damaged at Chickamauga to be trusted with major assaults. His plan assigned the glory roles to other armies. Veterans from the Army of the Potomac, fresh from their victory at Gettysburg, would take Lookout Mountain. Troops from the Army of the Tennessee, who had just secured the Siege of Vicksburg, would strike the Confederate right flank on Missionary Ridge. The Army of the Cumberland was handed a more modest assignment: seize the rifle pits at the base of the ridge.
They took the rifle pits. Then something unplanned happened. Four divisions, one of them led by Philip H. Sheridan, kept going. They stormed straight up Missionary Ridge without orders and broke the Confederate center entirely. Grant was furious. He demanded to know who had ordered the charge. Both Thomas and corps commander Gordon Granger said they did not know. Granger offered the only explanation available: "Once those boys get started, all hell can't stop 'em."
Grant's victory at Chattanooga earned him promotion to general-in-chief of the entire U.S. Army, and Major General William T. Sherman stepped into command of the Military Division of the Mississippi. In May 1864, Sherman assembled an army group drawing from the Army of the Cumberland, the Army of the Tennessee, and the Army of the Ohio, then marched it toward Atlanta. The campaign was long and costly, with engagements including the Battle of Kennesaw Mountain. Atlanta fell to Sherman's force in September 1864.
With Atlanta secured, Confederate General John B. Hood moved his army north. Sherman chose not to chase him. Instead he sent IV Corps and a Provisional Detachment from the Army of the Cumberland, along with XXIII Corps from the Army of the Ohio, to deal with Hood under Thomas's command. Thomas met Hood at the Battle of Nashville and crushed him, effectively ending major operations for the Army of the Cumberland.
The army's remaining elements took a different road entirely. The XIV and XX Corps marched with Sherman to the sea and then north through the Carolinas, commanded by Major General Henry W. Slocum. These forces were redesignated the Army of Georgia and, in 1865, paraded through Washington, D.C., in the Grand Review of the Armies before President Andrew Johnson.
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Common questions
What was the Army of the Cumberland's original name?
The Army of the Cumberland was originally called the Army of the Ohio. It was created in November 1861 under Brigadier General Robert Anderson, and was renamed when Major General William S. Rosecrans took command and merged the army with the Department of the Cumberland in October 1862.
Who commanded the Army of the Cumberland during the Civil War?
The Army of the Cumberland had two primary commanders. Major General William S. Rosecrans led the army from the 24th of October 1862 until the 19th of October 1863, overseeing the battles of Stones River, the Tullahoma Campaign, and Chickamauga. Major General George H. Thomas then commanded the army from October 1863 through August 1865, leading it through Chattanooga, the Atlanta Campaign, and Nashville.
Why was Rosecrans replaced as commander of the Army of the Cumberland?
Rosecrans was replaced because of his defeat at the Battle of Chickamauga and his inability to break the Confederate siege of Chattanooga. Ulysses S. Grant arrived at Chattanooga on the 19th of October 1863 and chose George H. Thomas as his replacement, despite Rosecrans having been a popular and respected commander.
What happened when the Army of the Cumberland charged up Missionary Ridge?
The Army of the Cumberland was assigned only to seize the rifle pits at the base of Missionary Ridge during the Battles for Chattanooga in 1863. After completing that limited objective, four divisions spontaneously stormed up the ridge and routed the Confederate center without orders. When Grant demanded to know who authorized the charge, both Thomas and corps commander Gordon Granger said they did not know.
What role did the Army of the Cumberland play in Sherman's March?
The Army of the Cumberland was a central component of Sherman's army group that captured Atlanta in September 1864. After Atlanta fell, part of the army under Thomas defeated Confederate General John B. Hood at the Battle of Nashville, while the XIV and XX Corps marched with Sherman to the sea and through the Carolinas under Major General Henry W. Slocum, designated the Army of Georgia.
What was the Grand Review of the Armies and did the Army of the Cumberland participate?
The Grand Review of the Armies was a victory parade held in Washington, D.C., before President Andrew Johnson in 1865. Elements of the Army of the Cumberland that had marched with Sherman, redesignated as the Army of Georgia under Major General Henry W. Slocum, participated in the review.