Remaining with the Union At the outbreak of the Civil War, 19 of the 36 officers in the 2nd U.S. Cavalry resigned, including three of Thomas's superiors—
Albert Sidney Johnston,
Robert E. Lee, and
William J. Hardee. Many
Southern-born officers were torn between loyalty to their states and loyalty to their country. Thomas struggled with the decision but opted to remain with the United States. His Northern-born wife probably helped influence his decision. In response, his family turned his picture against the wall, destroyed his letters, and never spoke to him again. During the economic hard times in the South after the war, Thomas sent some money to his sisters, who angrily refused to accept it, declaring they had no brother. Nevertheless, Thomas stayed in the Union Army with some degree of suspicion surrounding him, despite his action concerning Twiggs. On January 18, 1861, a few months before
Fort Sumter, he had applied for a job as the commandant of cadets at the
Virginia Military Institute. Any real tendency to the secessionist cause, however, could be refuted when he turned down
Virginia Governor John Letcher's offer to become chief of
ordnance for the Virginia Provisional Army. On June 18, his former student and fellow Virginian, Confederate Col.
J.E.B. Stuart, wrote to his wife, "Old George H. Thomas is in command of the cavalry of the enemy. I would like to hang,
hang him as a traitor to his native state." Nevertheless, as the Civil War carried on, he won the affection of Union soldiers serving under him as a "soldier's soldier", who took to affectionately referring to Thomas as "Pap Thomas".
Kentucky Thomas was promoted in rapid succession to be
lieutenant colonel (on April 25, 1861, replacing Robert E. Lee) and
colonel (May 3, replacing Albert Sidney Johnston) in the
regular army, and
brigadier general of volunteers (August 17). In the
First Bull Run Campaign, he commanded a brigade under
Maj. Gen. Robert Patterson in the
Shenandoah Valley, but all of his subsequent assignments were in the Western Theater. Reporting to Maj. Gen.
Robert Anderson in
Kentucky, Thomas was assigned to train recruits and command an independent force at Camp Dick Robinson in Garrard County, boosting the Union presence in central Kentucky and demonstrating federal resolve to Confederate forces gathering at Cumberland Gap and Barbourville in eastern Kentucky. Thomas led this command, which eventually became the First Division of the Army of the Ohio, to victory at
Mill Springs, defeating Confederate Brig. Gens.
George B. Crittenden and
Felix Zollicoffer, and gaining the first important Union victory in the war. This victory significantly diminished Confederate strength in eastern Kentucky and lifted Union morale nationally.
Shiloh and Corinth On December 2, 1861, Brig. Gen. Thomas was assigned to command the 1st Division of Maj. Gen.
Don Carlos Buell's
Army of the Ohio. He missed the
Battle of Shiloh (April 7, 1862), arriving after the fighting had ceased. The victor at Shiloh, Maj. Gen.
Ulysses S. Grant, came under severe criticism for the bloody battle due to the surprise and lack of preparations and his superior, Maj. Gen.
Henry W. Halleck, reorganized his Department of the Mississippi to ease Grant out of direct field command. The three armies in the department were divided and recombined into three "wings". Thomas, promoted to major general effective April 25, 1862, was given command of the Right Wing, consisting of four divisions from Grant's former
Army of the Tennessee and one from the Army of the Ohio. Thomas successfully led this force in the
siege of Corinth. On June 10, Grant returned to command of the original Army of the Tennessee.
Perryville, Stones River, Chickamauga, and Chattanooga , afternoon and evening of September 20, 1863 Thomas resumed service under
Don Carlos Buell. During Confederate General
Braxton Bragg's invasion of Kentucky in the fall of 1862, the Union high command became nervous about Buell's cautious tendencies and offered command of the Army of the Ohio to Thomas, who refused, as Buell's plans were too far advanced. Thomas served as Buell's second-in-command at the
Battle of Perryville, but his wing of the army did not hear the fighting engaged in by the other flank. Although tactically inconclusive, the battle halted Bragg's invasion of Kentucky as he voluntarily withdrew to Tennessee. Again frustrated with Buell's ineffective pursuit of Bragg, the government replaced him with Maj. Gen.
William Rosecrans. Thomas wrote on October 30, 1862, a letter of protest to Secretary Stanton, because Rosecrans had been junior to him, but Stanton wrote back on November 15, telling him that this was not the case (Rosecrans had in fact been his junior, but his commission as major general had been backdated to make him senior to Thomas) and reminding him of his earlier refusal to accept command; Thomas demurred and withdrew his protest. Fighting under Rosecrans, commanding the
"Center" wing of the newly renamed
Army of the Cumberland, Thomas gave an impressive performance at the
Battle of Stones River, holding the center of the retreating Union line and once again preventing a victory by Bragg. He was in charge of the most important part of the maneuvering from
Decherd to
Chattanooga during the
Tullahoma Campaign (June 22 – July 3, 1863) and the crossing of the
Tennessee River. At the
Battle of Chickamauga on September 19, 1863, now commanding the
XIV Corps, he once again held a desperate position against Bragg's onslaught while the Union line on his right collapsed. Thomas rallied broken and scattered units together on Horseshoe Ridge to prevent a significant Union defeat from becoming a hopeless rout. Future president
James Garfield, a field officer for the Army of the Cumberland, visited Thomas during the battle, carrying orders from Rosecrans to retreat; when Thomas said he would have to stay behind to ensure the Army's safety, Garfield told Rosecrans that Thomas was "standing like a rock." After the battle he became widely known by the nickname "The Rock of Chickamauga", representing his determination to hold a vital position against strong odds. , November 24–25, 1863 Thomas succeeded Rosecrans in command of the
Army of the Cumberland shortly before the
Battles for Chattanooga (November 23–25, 1863), a stunning Union victory that was highlighted by Thomas's troops taking Lookout Mountain on the right and then storming the Confederate line on
Missionary Ridge, the next day. When the Army of the Cumberland advanced further than ordered, General Grant, on Orchard Knob asked Thomas, "Who ordered the advance?" Thomas replied, "I don't know. I did not."
Atlanta and Franklin/Nashville During Maj. Gen.
William Tecumseh Sherman's advance through Georgia in the spring of 1864, the Army of the Cumberland numbered over 60,000 men, and Thomas's staff did the logistics and engineering for Sherman's entire army group, including developing a novel series of
Cumberland pontoons. At the
Battle of Peachtree Creek (July 20, 1864), Thomas's defense severely damaged
Lt. Gen. John B. Hood's army in its first attempt to break the siege of Atlanta. When Hood broke away from Atlanta in the autumn of 1864, menaced Sherman's long line of communications, and endeavored to force Sherman to follow him, Sherman abandoned his communications and embarked on the
March to the Sea. Thomas stayed behind to fight Hood in the
Franklin-Nashville Campaign. Thomas, with a smaller force, raced with Hood to reach Nashville, where he was to receive reinforcements. At the
Battle of Franklin on November 30, 1864, a large part of Thomas's force, under command of Maj. Gen.
John M. Schofield, dealt Hood a strong defeat and held him in check long enough to cover the concentration of Union forces in Nashville. At Nashville, Thomas had to organize his forces, which had been drawn from all parts of the West and which included many raw troops and even quartermaster employees. He declined to attack until his army was ready and the ice covering the ground had melted enough for his men to move. General Grant (now general-in-chief of all Union armies) grew impatient at the delay. Grant sent Maj. Gen.
John A. Logan with an order to replace Thomas, and soon afterwards Grant started a journey west from City Point, Virginia to take command in person. Thomas attacked on December 15, 1864, and the
Battle of Nashville effectively destroyed Hood's army in two days of fighting. Thomas sent his wife, Frances Lucretia Kellogg Thomas, the following telegram, the only communication surviving of the Thomases' correspondence: "We have whipped the enemy, taken many prisoners and considerable artillery." Thomas was appointed a major general in the regular army, with date of rank of his Nashville victory, and received the
Thanks of Congress: Thomas may have resented his delayed promotion to major general (which made him junior by date of rank to
Sheridan); upon receiving the telegram announcing it, he remarked to Surgeon George Cooper: "I suppose it is better late than never, but it is too late to be appreciated. I earned this at Chickamauga.". Thomas also received another nickname from his victory: "The Sledge of Nashville". ==Later life and death==