Army of the Trans-Mississippi Department

1863–1865

The last major Southern force to surrender at the end of the American Civil War, the Army of the Trans-Mississippi Department embodied the troops assigned to the Trans-Mississippi Department.

Portrait of Edmund Kirby Smith.

General Kirby Smith commanded the Trans-Mississippi Department and the Army of the Trans-Mississippi Department from 1863 to 1865. [Wikimedia Commons]

Prelude

At the onset of the American Civil War, the Confederate government organized its territory into military departments which were often, but not always, named for the states in which they operated. As the war progressed, it subdivided departments into smaller, more manageable divisions.

Department and division commanders were generals in the Confederate Army who handled all military matters within their domain. The vagaries of war often required the reorganization of department and division designations, as well as commanders. Thus, during the war, the Confederate military structure comprised over forty departments.

Trans-Mississippi Department

Origins

On June 25, 1861, Confederate President Jefferson Davis created Department No. 2, also known as the Western Department, to administer military operations west of the Appalachian Mountains. On September 10, 1861, Davis issued Special Orders, No. 149 (CSA) appointing General Albert Sidney Johnston to the command of Department No. 2, which embraced “the States of Tennessee and Arkansas and that part of the State of Mississippi west of the New Orleans, Jackson and Great Northern and Central Railroad; also, the military operations in Kentucky, Missouri, Kansas, and the Indian country immediately west of Missouri and Arkansas.” In effect, Davis placed Johnston in charge of most Confederate military operations in the West. Seven months later, on April 6, 1862, Johnston died from injuries he received at the Battle of Shiloh.

As pressing events in Kentucky and Tennessee demanded Johnston’s attention, a growing feud between Major General Sterling Price, who commanded the Missouri State Guard, and Brigadier-General Ben McCulloch, who commanded the Army of the West, was hindering Confederate operations west of the Mississippi River. On January 10, 1862, Confederate President Jefferson Davis attempted to resolve the discord by creating the Trans-Mississippi District within Department No. 2. Davis named Major General Earl Van Dorn to command the new district covering Missouri, Arkansas, the Indian Territory, and northern Louisiana.

On January 29, Van Dorn assumed command and established his headquarters at Pocahontas, Arkansas. He then organized many of the soldiers in the new district into the Army of the West, composed of two divisions commanded by McCulloch and Price. Van Dorn developed ambitious plans to sweep through Missouri, capture St. Louis, and threaten Union operations in Kentucky. Brigadier General Samuel R. Curtis, commanding the Union Army of the Southwest, dashed Van Dorn’s plans with a resounding federal victory at the Battle of Pea Ridge, in Benton County, Arkansas, on March 6–8, 1862.

Curtis’ success at the largest battle west of the Mississippi during the American Civil War forced Van Dorn to move the remnants of his tattered Army of the West across the Mississippi River. Shortly thereafter, the Confederate command structure west of the Mississippi underwent a series of rapid changes.

On May 26, 1862, the Adjutant and Inspector General’s Office of the Confederate War Department issued General Orders, No. 39, announcing the separation of the District of the Trans-Mississippi from Department No. 2, and the creation of the new Department of the Trans-Mississippi. The orders stated, “The boundary of the Trans-Mississippi Department will embrace the States of Missouri and Arkansas, including the Indian Territory, the State of Louisiana west of the Mississippi River, and the State of Texas.” Brigadier General Paul Octave Hébert, former governor of Louisiana, temporarily commanded the new department until June 20, 1862. Following Hébert were Major General Thomas C. Hindman (June 20–July 16, 1862) and Major General Theophilus H. Holmes (July 30, 1862–February 9, 1863).

Kirby-Smithdom

Command of the Trans-Mississippi Department began stabilizing on February 9, 1863, when Confederate Adjutant and Inspector General Samuel Cooper informed Lieutenant General Edmund Kirby Smith that “Your command of Southwestern Army has been enlarged so as to embrace the Trans-Mississippi Department.” (Cooper to Smith correspondence via General Pemberton. Also see Special Orders, No. 33, Confederate Adjutant and Inspector General’s Office). Smith traveled to Alexandria, Louisiana, where he assumed command on March 7, 1863. Aside from a three-day period when he was on leave, Smith led the department and its forces until the end of the war.

Shortly after Smith assumed command, Union forces captured Vicksburg, Mississippi, (July 4, 1863) and Port Hudson, Louisiana, (July 9, 1863), and seized control of the Mississippi River, splitting the Confederacy east to west. On July 28, 1863, Smith wrote to Confederate Adjutant and Inspector General Samuel Cooper requesting him to ask President Jefferson Davis to grant Smith “extraordinary powers for the organization of a government” west of the Mississippi River. On September 12, Smith again requested extended powers from Davis. Although there is scant evidence that Davis ever granted Smith’s request, by default, Smith gradually assumed expanded powers because the Trans-Mississippi Department remained isolated from the Confederate government for the rest of the war. Smith’s military authority west of the Mississippi River was so complete that contemporaries sometimes referred to the Department of the Trans-Mississippi as “Kirby-Smithdom.”

Department Commanders

During its three years of existence, five men commanded the Department of the Trans-Mississippi;

  • Brigadier General Paul Octave Hébert, former governor of Louisiana, (May 26–June 20, 1862)
  • Major General Thomas C. Hindman (June 20–July 16, 1862)
  • Major General Theophilus H. Holmes (July 30, 1862–February 9, 1863)
  • Lieutenant General Edmund Kirby Smith (February 9, 1863–April 19, 1865). (Smith assumed command on March 7, 1863)
  • Major General Simon Bolivar Buckner (April 19–22, 1865)
  • Lieutenant General Edmund Kirby Smith (April 22–May 26, 1865)

Army of the Trans-Mississippi Department

Origins

The origins of the Army of the Trans-Mississippi Department come from Special Orders, No. 39, issued on September 28, 1862, by Major General Theophilus H. Holmes, commander of the Trans-Mississippi Department. Holmes’ order declared that “Major General T. C. Hindman… will assume command of the troops in Northwestern Arkansas, Southwestern Missouri, and the Indian Territory, and will organize the same into an army corps, to be styled First Army Corps, Army of the West.”

After Lieutenant General Kirby Smith assumed command of the Trans-Mississippi Department on March 7, 1863, Hindman’s corps was reorganized to include all combat forces in the department.

Possibly because of the isolation of the Trans-Mississippi Department from the Confederate government, there are no extant records officially designating a name for the troops under Kirby Smith’s command. Consequently, historians usually refer to the forces in Smith’s department as the Army of the Trans-Mississippi Department.

Size

Although records are inexact, the size of the army at its largest may have topped 50,000 soldiers. By the end of the war, casualties and desertion reduced the army’s numbers considerably below 40,000 men.

Structure

At its peak, in 1864, the Army of the Trans-Mississippi Department consisted of three infantry corps, one cavalry corps, and a reserve corps.

  • I Corps (Headquartered at Shreveport, Department of Louisiana), originally established in 1862. Reorganized on August 4, 1864, under command of Simon Bolivar Buckner.
  • II Corps (Department of Arkansas and Missouri), created on August 4, 1864, under command of John B. Magruder.
    III Corps (Headquartered at Galveston, Department of Texas), created on August 4, 1864, under command of John George Walker.
  • Trans-Mississippi Army Cavalry Corps, created on August 4, 1864, under command of Sterling Price.
  • Reserve Corps, established on September 10, 1864, under command of Jerome B. Robertson, succeeded on September 12, 1864, by Thomas P. Dockery, succeeded on March 17, 1865, by Elkanah B. Greer (to May 1865)

Notable Officers

  • Edmund Kirby Smith
  • Sterling Price
  • Simon Bolivar Buckner
  • Richard Taylor
  • John B. Magruder
  • John George Walker
  • James Fleming Fagan
  • John S. Marmaduke
  • Joseph O. Shelby
  • Samuel B. Maxey
  • Thomas James Churchill
  • Mosby M. Parsons

Campaigns

During its existence under Kirby Smith’s command, soldiers from the Army of the Department of the Trans-Mississippi took part in three major campaigns.

Red River Campaign (March 10–May 22, 1864)

In March 1864, Union authorities launched two offensives to gain control of the Trans-Mississippi region. Although the Yankees outnumbered Smith’s army, he engineered the defeat of both Northern advances. On April 8, Confederate troops commanded by Major General Richard Taylor repulsed Union forces commanded by Major General Nathaniel Banks with a decisive victory at the Battle of Mansfield, spelling defeat for Bank’s Red River Campaign.

Camden Expedition (March 23–May 3, 1864)

Concurrent with Bank’s Red River Campaign, Major General Frederick Steele led the Union Army of Arkansas (aka VII Corps) into Arkansas to end the Confederate presence in that state. Smith responded by dispatching Major General Sterling Price’s Cavalry Corps northward to foil Steele’s Camden Expedition.

Price’s Missouri Expedition (August 29–December 2, 1864)

In August 1864, Smith detached 12,000 soldiers from the Army of the Trans-Mississippi to conduct a raid into Missouri. Led by Sterling Price, who named his force the Army of Missouri, the raid was designed to bolster Confederate influence in the West, divert Union troops away from the Eastern Theater, and damage U.S. President Abraham Lincoln’s reelection ambitions. Price’s Raid began on August 28, 1864, when he departed from Camden, Arkansas. A little over three months and a dozen or more battles later, Price limped back into Arkansas, having lost roughly one-third of the soldiers who followed him into Missouri.

Surrender and Dissolution

In April 1865, Confederate Generals Robert E. Lee and Joseph Johnston surrendered their armies, essentially ending the war in the East. Following the surrender in the East, the Army of the Trans-Mississippi rapidly disintegrated as soldiers simply walked away and returned home.

As his army evaporated, Kirby Smith held on for roughly another month. Abandoning his headquarters in Shreveport, Louisiana on May 18, Smith headed for Galveston, Texas, leaving Major General Simon Buckner in charge. During the week that it took Smith to reach Galveston, the command structure of the Army of the Trans-Mississippi Department nearly ceased to exist.

On May 25, Buckner and Sterling Price traveled to New Orleans, where they met with a Union delegation headed by Major General Edward R. S. Canby to hammer out terms of surrender of the Army of the Trans-Mississippi Department, subject to Kirby Smith’s approval. The following day, Buckner and Canby’s chief of staff, General P. J. Osterhaus, signed a “military convention” stipulating the same terms given Lee in Virginia and Johnston in North Carolina.

On May 27, Kirby Smith reached Galveston and learned that Buckner had surrendered most of the Army of the Trans-Mississippi Department. After considering his options, on June 2, 1865, Smith accepted the undeniable. He issued several special orders facilitating the final surrender of the army. He then fled to Mexico to avoid prosecution for treason.

Although Brigadier General Stand Watie’s 1st Cherokee Mounted Rifles (a part of the Army of the Trans-Mississippi Department) remained in the field until June 23, 1865, the Army of the Trans-Mississippi Department was the last major Confederate force to surrender at the end of the Civil War.

Contributions

During its existence, the Trans-Mississippi Department and its army served the Confederacy by guarding the international border with Mexico, protecting seaports in Texas and Louisiana, and maintaining a steady flow of cotton to the East and for export overseas, until the Union seized control of the Mississippi River.

Citation Information

The following information is provided for citations.

  • Article Title Army of the Trans-Mississippi Department
  • Date 1863–1865
  • Author
  • Website Name American History Central
  • Access Date September 28, 2023
  • Publisher R.Squared Communications, LLC
  • Original Published Date
  • Date of Last Update July 5, 2022

Army of the Trans-Mississippi Department is Part of the Following on AHC