February 23, 1862–October 26, 1862
Created on February 23, 1862, the Army of the Mississippi participated in the Battle of Island No. 10, the Siege of Corinth, the Battle of Iuka, and the Battle of Corinth II, before being discontinued on October 26, 1862.
On November 9, 1861, the United States War Department issued General Orders No. 97, which divided the Western Department into the Department of New Mexico, the Department of the Ohio, the Department of Western Virginia, and the Department of the Missouri. The directive appointed Major General Henry Halleck as commander of the latter.
In February 1862, Halleck organized the Union troops operating in the State of Missouri, creating the Army of the Mississippi. Halleck named Brigadier-General John Pope as commander of the new army. Pope assumed command on February 23 and established his headquarters at Commerce, Missouri. Initially, the small army consisted of only two divisions.
In March, the size of the Army of the Mississippi swelled to nearly 25,000 soldiers, in preparation for Pope's advance on the Mississippi River town of New Madrid, Missouri. At its largest extent, the army consisted of five infantry divisions, a flotilla brigade, and several brigades of cavalry. The infantry division commanders were Brigadier-Generals David S. Stanley, Schuyler Hamilton, John M. Palmer, Eleazar A. Paine, and Joseph B. Plummer. Brigadier-General Gordon Granger commanded the cavalry division of two regiments, and Colonel Napoleon B. Buford led the flotilla brigade.
On March 14, 1862, the Army of the Mississippi forced the withdrawal of Confederate troops from New Madrid to Island No. 10 on the Mississippi River. Then, with the assistance of Flag Officer Andrew Hull Foote's naval forces, Pope subdued the Confederate garrison on the island on April 7, 1862, taking nearly seven thousand prisoners, while suffering fewer than one hundred casualties. Pope's victory gave the Union control of the river as far south as Memphis, Tennessee.
On April 17, 1862, Pope's command sailed to Hamburg Landing on the Tennessee River and joined the Union advance upon Corinth, Mississippi. The Army of the Mississippi participated in the Siege of Corinth from April 29 to May 30, 1862, serving on the extreme left of the Union army.
In June 1862, President Lincoln summoned Pope east to take command of the newly-created Army of Virginia. On June 26 Brigadier-General William S. Rosecrans succeeded Pope as commander of the Army of the Mississippi.
On July 11, 1862, President Abraham Lincoln telegraphed Halleck that he was being promoted to General-in-Chief of the Union Army, effective July 23. Ulysses S. Grant became the de-facto commander of the Department of the Missouri, because no one was assigned to the position, and Grant made his reports directly to Halleck.
During that period, Grant detached the 2nd and 6th Divisions of the Army of West Tennessee to join the Army of the Mississippi garrisoned at Corinth. Bolstered by the two additional divisions, the Army of the Mississippi participated in the Union victory at Battle of Iuka (September 19, 1862). Afterward, the combined force returned to Corinth, where it successfully defended the town from a Confederate attack at the Battle of Corinth II on October 3 and 4, 1862.
Shortly after the Battle of Corinth II, the War Department issued General Orders No. 159, on October 16, 1862, placing Ulysses S. Grant in command of the newly-created Department of the Tennessee. Grant took command on October 25. The Army of the Mississippi ceased to exist the next day, when Grant issued General Orders No. 2, Department of the Tennessee, stating, "The army heretofore known as the 'Army of the Mississippi,' being now divided and in different Departments, will be discontinued as a separate Army."
Ohio Volunteer Infantry Regiments that served with the Army of the Mississippi:
27th Regiment Ohio Volunteer Infantry
39th Regiment Ohio Volunteer Infantry
43rd Regiment Ohio Volunteer Infantry
63rd Regiment Ohio Volunteer Infantry
80th Regiment Ohio Volunteer Infantry
102nd Regiment Ohio Volunteer Infantry
106th Regiment Ohio Volunteer Infantry
115th Regiment Ohio Volunteer Infantry
173rd Regiment Ohio Volunteer Infantry
174th Regiment Ohio Volunteer Infantry
175th Regiment Ohio Volunteer Infantry
176th Regiment Ohio Volunteer Infantry
177th Regiment Ohio Volunteer Infantry
178th Regiment Ohio Volunteer Infantry
179th Regiment Ohio Volunteer Infantry
180th Regiment Ohio Volunteer Infantry
181st Regiment Ohio Volunteer Infantry
182nd Regiment Ohio Volunteer Infantry
184th Regiment Ohio Volunteer Infantry
188th Regiment Ohio Volunteer Infantry
Ohio Volunteer Cavalry Regiments that served with the Army of the Mississippi:
5th Regiment Ohio Volunteer Cavalry
Ohio Volunteer Artillery Regiments that served with the Army of the Mississippi:
3rd Regiment Ohio Volunteer Light Artillery
4th Regiment Ohio Volunteer Light Artillery
5th Regiment Ohio Volunteer Light Artillery
7th Regiment Ohio Volunteer Light Artillery
8th Regiment Ohio Volunteer Light Artillery
10th Regiment Ohio Volunteer Light Artillery
11th Regiment Ohio Volunteer Light Artillery
13th Regiment Ohio Volunteer Light Artillery
14th Regiment Ohio Volunteer Light Artillery
15th Regiment Ohio Volunteer Light Artillery
17th Regiment Ohio Volunteer Light Artillery
- Ulysses S. Grant
- Henry Wager Halleck
- William Starke Rosecrans
- Ohio Volunteer Infantry
- Battle of Corinth II
- Battle of Iuka
- Abraham Lincoln
- John Pope
- General Orders, No. 97 (Headquarters of the Army)
- General Orders, No. 159 (U.S. War Department)
- Army of West Tennessee
- Siege of Corinth
- Gordon Granger
- Operations at New Madrid and Island No. 10
- David Sloane Stanley