During the American Civil War, there were two Union armies designated as the Army of the Ohio. The first Army of the Ohio existed during the years 1861 and 1862.
On April 15, 1861, one day after the surrender of Fort Sumter propelled the nation into civil war, President Abraham Lincoln issued a proclamation calling for seventy-five thousand state militiamen to suppress the Southern rebellion. Thousands of loyal men throughout the Midwest were quick to respond. The rapid buildup of local regiments required the United States War Department to create structure out of chaos. On May 3, 1861, Washington officials issued General Orders Number 14, which created a new military unit known as the Department of the Ohio, consolidating regiments from the states of Ohio, Indiana, and Illinois. Commanded by Major General George B. McClellan, the new department was headquartered at Cincinnati, Ohio. McClellan oversaw the department until he was assigned command of the Division of Washington pursuant to General Orders No. 47, dated July 25, 1861. Following McClellan's departure, Brigadier-General Ormsby M. Mitchel commanded the Department of the Ohio from September 19 to November 15, 1861.
Meanwhile, south of the Ohio River, Kentucky officials were attempting to avoid involvement in the insurrection. One day after Lincoln issued his call for volunteers, Kentucky Governor Beriah Magoffin tersely responded that Kentucky would provide no troops. On May 24, the Kentucky legislature passed a resolution officially declaring the state's neutrality.
Despite Kentucky's efforts to remain neutral, recruiters on both sides were actively engaged throughout the state. By May 28, 1861, enough pro-Union regiments had been raised to prompt the U.S. War Department to organize the Department of Kentucky, which included as much of the state of Kentucky that lay within one hundred miles of the Ohio River. Brigadier-General Robert Anderson, who had recently surrendered Fort Sumter, was chosen to command the new department.
On August 15, 1861, the War Department issued General Orders Number 57, which effectively replaced the Department of Kentucky with an expanded department that included all of Kentucky and Tennessee. The newly created unit was named Department of the Cumberland. During Anderson's tenure, troops commanded by Confederate General Leonidas Polk invaded Columbus, Kentucky, ending all illusions that the state would escape the War Between the States. Within one week, voters in Kentucky elected a new Unionist legislature that voted to end the state's neutrality.
On October 7, 1861, the War Department issued General Orders Number 6, directing Major-General William T. Sherman to relieve Anderson, who had taken ill. Assuming command of the department on October 8, Sherman issued General Orders Number 7.
One month later, when Sherman began to act erratically due to stress, he asked to be relieved of his command. On November 9, 1861, the War Department issued General Orders Number 97, which dissolved the Department of the Cumberland and expanded the Department of the Ohio to include the states of Ohio, Indiana, Michigan, Tennessee, and Kentucky east of the Cumberland River. Brigadier-General Don Carlos Buell was selected to command the department, with headquarters at Louisville, Kentucky. When Buell assumed command on November 15, 1861, he found the structure, discipline, and training of troops under his command to be lacking and immediately set about remedying the situation. By December, Buell had organized the forces under his command into five divisions that would henceforth be known as the Army of the Ohio.
On January 19, 1862, the Army of the Ohio defeated Confederate troops commanded by Major- General George B. Crittenden at the Battle of Mill Springs, Kentucky. The Union victory forced the Rebels to abandon eastern Kentucky and to retreat into Tennessee.
Buell's army then moved southeast toward Nashville. On February 25, 1862, the Army of the Ohio marched into the Tennessee capital unopposed, making Nashville the first Confederate state capital to fall into Union hands during the Civil War.
Shortly after the occupation of Nashville, President Lincoln issued War Order Number 3, which consolidated three western departments, including the Department of the Ohio into the Department of the Mississippi, commanded by Major-General Henry Halleck. The Army of the Ohio, still under Buell's command, consisted of 94,783 men, with 73,472 of these soldiers combat ready.
While Lincoln was reorganizing his armies in the West, Confederate General Joseph E. Johnston was consolidating his forces at Corinth, Mississippi, where the Western and Charleston Railroad and the Ohio and Mobile Railroad intersected. In preparation for a general move against Corinth, Halleck ordered Buell to move the Army of Ohio to Savanah, Tennessee, located on the eastern bank of the Tennessee River, approximately thirty-five miles north of Corinth. From there, the Army of the Ohio moved nearly ten miles downstream, on April 6, 1861, to support Major-General Ulysses S. Grant's Army of the Tennessee on the first day of the Battle of Shiloh. Buell's arrival near sunset boosted the morale of Grant's weary troops and enabled Grant to take the offensive and to win the battle on the next day.
Following the Battle of Shiloh, Halleck arrived at Pittsburg Landing on April 11, andhe personally took charge of all of his forces. Halleck organized his troops into left, center, and right wings. Buell's Army of the Ohio comprised the center wing. Halleck then advanced cautiously toward Corinth over the next two weeks. Following a short siege, he occupied Corinth, after the Rebel forces, commanded by General P.G.T. Beauregard, escaped unscathed.
In the wake of the loss of Corinth, Confederate President Jefferson Davis relieved General P.G.T. Beauregard of command of the Army of Mississippi on June 27, 1862 and replaced him with Braxton Bragg. The focus of the war in Tennessee moved east to Chattanooga. Halleck ordered Buell to capture the important rail hub, but facing fewer logistical obstacles, Bragg beat him to it.
As Buell approached Chattanooga, Bragg went on the offensive and launched an invasion of Kentucky, threatening Buell's supply lines back to Louisville. Bragg left Chattanooga in August with nearly thirty-four thousand men, with plans to unite with Lieutenant General Edmund Kirby Smith's eighteen thousand soldiers, stationed near Knoxville, Tennessee, and then to move against the Army of the Ohio.
Initially, events went well for the Confederates. Smith left Knoxville on August 14, 1862, and he defeated a Union garrison at Richmond, Kentucky on August 30. Bragg's army captured an important rail station, along with four thousand Union soldiers, at the Battle of Munfordville (September 14-17, 1862). Throughout September, the two-headed Rebel onslaught forced Buell back towards Louisville. There, soldiers from across the Ohio River reinforced the Army of the Ohio. In early October, with up to sixty thousand men under his command, Buell left Louisville and became the pursuer. Smith and Bragg had still not combined their armies, and the Confederates were unprepared for Buell's advance.
On October 7, 1862, Buell's army approached the small crossroads town of Perryville, Kentucky in three columns. There, the first column to arrive, commanded by Major General Alexander M. McCook, engaged sixteen thousand of Bragg's men, commanded by Major General Leonidas Polk. Bragg rushed to Perryville and took command by 10:00 a.m. on October 8. Facing stubborn resistance, the Rebels gradually drove the Federals back. As the day progressed, however, more of Buell's army arrived on the scene. Running short of supplies and ammunition and faced with the prospect of squaring off with the bulk of the Army of the Ohio on the following day, Bragg withdrew during the night, despite suffering fewer casualties and achieving a tactical victory at the Battle of Perryville.
After the Battle of Perryville, Bragg retreated to Harrodsburg, Kentucky, where he finally joined forces with Kirby Smith. The combined Confederate force was now comparable in size to the Army of the Ohio. Nevertheless, Bragg lost his enthusiasm for the campaign. Over the objections of Smith, Polk, and other subordinates, Bragg decided to call off the Confederate Heartland Campaign and to evacuate Kentucky, leaving the state in Union control for the remainder of the war.
Buell's half-hearted pursuit of Bragg as the Confederates withdrew from Kentucky, combined with his slow advance toward Chattanooga during the summer, triggered a great deal of criticism from Washington. Consequently, on October 24, 1862, the War Department issued General Orders Number 168, which created the Department of the Cumberland, encompassing all of Tennessee east of the Tennessee River, plus any parts of northern Alabama and Georgia that might be captured United States troops. The directive went on to place Major General William Rosecrans in charge of all U.S forces within the new department, including the Army of the Ohio. A dispatch from Halleck to Buell on the same day relieved Buell of his command.
General Orders Number 168 also designated all of Rosecrans's forces as the 14th Corps, thus ending the existence of the Army of the Ohio. The 14th Corps soon became known as the Army of the Cumberland, re-acquiring its designation from the days of Anderson’s and Sherman's command in 1861. The Army of the Cumberland went on to serve with valor during the Battle of Stones River (December 31, 1862–January 2, 1863), the Battle of Chickamauga (September 19-20, 1863), the Chattanooga Campaign (October-November, 1863), the Atlanta Campaign (May 7-September 2, 1864), and the Franklin-Nashville Campaign (September 18-December 27, 1864).
Ohio Volunteer Infantry Regiments that served with the first Army of the Ohio:
1st Regiment Ohio Volunteer Infantry (3 years)
2nd Regiment Ohio Volunteer Infantry (3 years)
3rd Regiment Ohio Volunteer Infantry (3 years)
6th Regiment Ohio Volunteer Infantry (3 years)
9th Regiment Ohio Volunteer Infantry (3 years)
10th Regiment Ohio Volunteer Infantry (3 years)
11th Regiment Ohio Volunteer Infantry (3 years)
12th Regiment Ohio Volunteer Infantry (3 years)
13th Regiment Ohio Volunteer Infantry (3 years)
14th Regiment Ohio Volunteer Infantry (3 years)
15th Regiment Ohio Volunteer Infantry (3 years)
16th Regiment Ohio Volunteer Infantry (3 years)
17th Regiment Ohio Volunteer Infantry (3 years)
18th Regiment Ohio Volunteer Infantry (3 years)
19th Regiment Ohio Volunteer Infantry (3 years)
21st Regiment Ohio Volunteer Infantry (3 years)
24th Regiment Ohio Volunteer Infantry
26th Regiment Ohio Volunteer Infantry
31st Regiment Ohio Volunteer Infantry
33rd Regiment Ohio Volunteer Infantry
35th Regiment Ohio Volunteer Infantry
36th Regiment Ohio Volunteer Infantry
38th Regiment Ohio Volunteer Infantry
40th Regiment Ohio Volunteer Infantry
41st Regiment Ohio Volunteer Infantry
42nd Regiment Ohio Volunteer Infantry
44th Regiment Ohio Volunteer Infantry
45th Regiment Ohio Volunteer Infantry
49th Regiment Ohio Volunteer Infantry
50th Regiment Ohio Volunteer Infantry
51st Regiment Ohio Volunteer Infantry
52nd Regiment Ohio Volunteer Infantry
59th Regiment Ohio Volunteer Infantry
64th Regiment Ohio Volunteer Infantry
65th Regiment Ohio Volunteer Infantry
69th Regiment Ohio Volunteer Infantry
74th Regiment Ohio Volunteer Infantry
79th Regiment Ohio Volunteer Infantry
83rd Regiment Ohio Volunteer Infantry
89th Regiment Ohio Volunteer Infantry
90th Regiment Ohio Volunteer Infantry
91st Regiment Ohio Volunteer Infantry
92nd Regiment Ohio Volunteer Infantry
93rd Regiment Ohio Volunteer Infantry
94th Regiment Ohio Volunteer Infantry
95th Regiment Ohio Volunteer Infantry
96th Regiment Ohio Volunteer Infantry
97th Regiment Ohio Volunteer Infantry
98th Regiment Ohio Volunteer Infantry
99th Regiment Ohio Volunteer Infantry
100th Regiment Ohio Volunteer Infantry
101st Regiment Ohio Volunteer Infantry
102nd Regiment Ohio Volunteer Infantry
103rd Regiment Ohio Volunteer Infantry
104th Regiment Ohio Volunteer Infantry
105th Regiment Ohio Volunteer Infantry
106th Regiment Ohio Volunteer Infantry
108th Regiment Ohio Volunteer Infantry
110th Regiment Ohio Volunteer Infantry
111th Regiment Ohio Volunteer Infantry
113th Regiment Ohio Volunteer Infantry
116th Regiment Ohio Volunteer Infantry
118th Regiment Ohio Volunteer Infantry
120th Regiment Ohio Volunteer Infantry
121st Regiment Ohio Volunteer Infantry
122nd Regiment Ohio Volunteer Infantry
123rd Regiment Ohio Volunteer Infantry
126th Regiment Ohio Volunteer Infantry
Ohio Volunteer Cavalry Regiments that served with the first Army of the Ohio:
1st Regiment Ohio Volunteer Cavalry
3rd Regiment Ohio Volunteer Cavalry
4th Regiment Ohio Volunteer Cavalry
Ohio Volunteer Artillery Regiments that served with the first Army of the Ohio:
6th Regiment Ohio Volunteer Light Artillery Regiment
9th Regiment Ohio Volunteer Light Artillery Regiment
17th Regiment Ohio Volunteer Light Artillery Regiment
18th Regiment Ohio Volunteer Light Artillery Regiment
19th Regiment Ohio Volunteer Light Artillery Regiment
- Pierre Gustave Toutant Beauregard
- Braxton Bragg
- Don Carlos Buell
- Ulysses S. Grant
- Henry Wager Halleck
- William Tecumseh Sherman
- Franklin-Nashville Campaign
- Battle of Perryville
- Battle of Mill Springs
- Battle of Stones River
- George Brinton McClellan
- Abraham Lincoln
- Jefferson Finis Davis
- Battle of Shiloh
- Siege of Corinth
- Alexander McDowell McCook
- Edmund Kirby Smith
- General Orders, No. 1 (Department of the Ohio, 1861)
- General Orders, No. 6 (Department of the Cumberland)
- General Orders, No. 47 (U.S. War Department)
- General Orders, No. 14 (U.S. War Department)
- General Orders, No. 57 (U.S. War Department) (1861)
- General Orders, No. 97 (Headquarters of the Army)
- General Orders, No. 7 (Department of the Cumberland)
- General Orders, No. 168 (U.S. War Department)
- Army of the Ohio 1863?1865
- General Orders, No. 168 (U.S. War Department)
- William Starke Rosecrans
- Battle of Chattanooga
- Battle of Chickamauga
- Chattanooga Campaign
- Atlanta Campaign
- Department of the Ohio
- Ormsby MacKnight Mitchel
- Army of the Tennessee
- Army of the Cumberland
- Robert Anderson
- Robert Anderson
- Leonidas Polk
- 1st Regiment Ohio Volunteer Cavalry
- 3rd Regiment Ohio Volunteer Cavalry
- Battle of Munfordville
- Confederate Heartland Offensive