Introduction to Confederate Organisations – Theatres
Western and Gulf Coast Theatre LINK
Eastern and Appalachian Theatre LINK
Atlantic Coast Theatre LINK
Trans-Mississippi and Frontier Theatres LINK
Staff Bureaux LINK
There was some deliberate planning in the evolution of the territorial and field commands of the Confederacy, but the first six months were characterised by improvisations in response to the most immediate threats. Whereas the US Regular Army had existing military Departments covering the entire mainland of the country, the Confederates established its first military commands at the initial points of threatened invasion and the remaining US military posts on its territory and coastline. Only then were these combined into a network of military commands encompassing the entire nation.
The first large-scale military organisation was unofficially named as the Department of Louisiana, with instructions to defend New Orleans, the most populous city of the South and the gateway to the Mississippi. The Confederates understood that the Mississippi River was its most vital strategic artery and access to it needed to be defended as an urgent priority. Furthermore, the Confederacy’s economic and strategic dependence on cotton exports required every possible port to be held open and their fortifications to be acquired by State or national troops.
The second development inevitably occurred around Charleston, SC, where the national crisis was focused on the US Army garrison holding out at Fort Sumter. The Department of South Carolina was formed at the beginning of March 1861 to organise state forces to achieve its reduction.
Unsurprisingly, very soon afterwards the third organisation to be formed was the Department of West Florida, to oppose the US garrison at Fort Pickens, at Pensacola, Florida.
The confrontation at Charleston would spark the outbreak of armed hostilities. Opportunism led to the emergence of the next Confederate command at Harper’s Ferry, Virginia, where the US Arsenal provided a windfall of much needed weapons, machinery, and supplies.
Plans to recruit an army and to mobilise the existing state militias for the occupation of Federal property continued apace but it would require the outbreak of actual hostilities for the Confederate Army to adopt its full form as a nationwide military organisation. For the coming conflict, the Confederacy followed the broad pattern of the United States, supplementing a comparatively small Regular Army with a temporarily army of volunteer recruits, called up for service of a limited duration. The main difference was that the Confederates never truly established a permanent and functional Regular Army.
Western Theatre and Gulf Coast Theatre
The Western Theatre broadly covers the states of Kentucky, Tennessee, Mississippi and adjacent operational regions in Louisiana, Florida Georgia, Illinois, Indiana, Ohio, South Carolina, and North Carolina.
The Gulf Coast Theatre broadly covers the western part of Florida, the eastern part of Louisiana, and the southern parts of Alabama, and Mississippi, and adjacent operational regions. From June 1862, it was effectively subordinated to the operations of the Western Theatre so it is described as part of the Western Theatre.
This was the decisive theatre of operations where the foundations of Union victory were firmly established. Being geographically central, operations in this theatre inevitably impinged on and overlapped with all the other theatres of war. Confederate military organisation evolved in response both to Union incursions and to facilitate offensive operations. The primary focus was on two main lines of possible advance by the Union Army, both assisted by naval forces on the inland rivers. The first followed the line of the Mississippi southwards and the second, followed the line of the Tennessee River into northern Georgia during 1862 to 1864. Exploitation of the latter advance in late 1864 and 1865 took dominant Union forces from the western theatre across Georgia to the Atlantic Coast and then north through the Carolinas.
The very first large-scale military organisation of the Confederacy was the Department of Louisiana, created before the outbreak of war to defend New Orleans, the most populous city of the South and the gateway to the Mississippi. The Confederates understood that the Mississippi River was a vital strategic artery and access to it needed to be defended as an urgent priority. Furthermore, the Confederacy’s economic and strategic dependence on cotton exports required every available port to be held open and their fortifications to be acquired by State or national troops. The unofficial Department was re-designated briefly as the District of Louisiana after war broke out, but the first significant Confederate formation was Department No 1, established on 27 May 1861, comprising the state of Louisiana except along the Mississippi River north of the 31st parallel: and also, southern Mississippi and southern Alabama including Mobile. The remainder of Mississippi, northwestern Louisiana, and Alabama came under the counterpart Department No 2 better known as the Western Department.
Department No 1 was responsible primarily for the defence of the Mississippi River, so the District of Alabama was established on 12 September 1861, to organise forces in the southern parts of Alabama east of the Pascagoula River. After just over a month, it was found more convenient to transfer this Alabama segment entirely under the new Department of Alabama and West Florida. After the fall of New Orleans, this Department saw little action and on 25 June 1862 it was discontinued, with the parts of Louisiana west of the Mississippi transferred to the Trans-Mississippi Department.
The Department of West Florida was formed before the war to oppose the US garrison at Fort Pickens, at Pensacola, Florida. On 7 October 1861, it was extended by the addition of parts of Alabama from Department No 1 and was renamed the Department of Alabama and West Florida. The subordinate District of Alabama was short-lived. The Confederates gathered and recruited a comparatively large force along the Gulf Coast, but the impossibility or undesirability of capturing Fort Pickens or Pensacola were soon apparent. The majority of the field forces were transferred to the operations in Tennessee and north Mississippi in early 1862. By the end of June 1862, the remaining commands were transferred to the supervision of the Western Department and remained subordinated to the strategic demands of that wider theatre.
Confederate military organisation necessarily evolved into two diverging and competing segments: one defending the Mississippi sector and the other protecting the invasion routes through Tennessee into Georgia. There were repeated efforts to coordinate the two sectors, but they were largely ineffective as resources were insufficient to strengthen either segment at the expense of the other without risking defeat in the weaker sector. The Confederates aspired repeatedly to launch aggressive counteroffensives, but their efforts floundered beyond the tactical level. The invasion of Kentucky in 1862 was an ambitious but fruitless enterprise, while the attacks at Shiloh and Corinth in 1862, Chickamauga in 1863 and Tennessee in 1864 showed a comparable aggression.
The initial military organisation coalesced around the Mississippi River, attempting to coordinate forces on the western and eastern banks, and on the disputed state of Kentucky. The Western Department (or, Department No 2) was formed on 25 June 1861 to organise forces on both banks of the Mississippi as far as north as Kentucky and west of the Tennessee River, while Department No 1 oversaw the southern stretches of the Mississippi. By September 1861, the Department had been extended to include northern Alabama, the parts of Mississippi and Louisiana along the Mississippi River, Kentucky, Tennessee, Missouri, Arkansas, and the Indian Territory. The Indian Territory was soon taken away as it was too distant for effective direction. Field forces collected around fortified strongholds along the Mississippi, Tennessee, and Cumberland, and attempted to become established in central and eastern Kentucky. The unexpected vulnerability of riverside forts to attack armoured by armoured warships undermined this strategy and as Union forces penetrated inland along the major rivers, the Confederate line of defence was forced back broadly to a line along the southern edge of Tennessee and the neighbouring states.
The difficulty of coordinating operations on both banks of the Mississippi was acknowledged in May 1862 and the Trans-Mississippi parts of the Western Department gained autonomy. The discontinuation of Department No 1 in June 1862 meant that the Department now controlled the vast theatre between the Mississippi, the Appalachian massif, and the Gulf of Mexico. This extension now added a third competing sector to the strategic challenge – the defence of the Gulf ports – but this remained a mercifully minor problem until late 1864.
The invasion of Kentucky in 1862, intended as a bold sweep to regain the territory as far north of the Ohio, necessitated the extension of the Department into mountainous East Tennessee and the emergence of what became the Department of Mississippi and East Louisiana and its army to hold the Mississippi live while the Army of Mississippi advanced from middle to join the Army of East Tennessee/Kentucky from eastern Tennessee in an uneasy collaboration.
There were desperate efforts to coordinate the operations of these three armies but to little avail so in November 1862, the first attempt to provide a clear strategic oversight was enacted with the formation of the Military Division of the West. General Joseph Eggleston Johnston led this supreme headquarters, but it was immediately apparent to him that it was impossible to meet all of his diverging priorities or to concentrate his field forces to gain a consistent ascendancy at any point. The merger of the Department of East Tennessee and the Western Department into the Department of Tennessee in July 1863 was a positive move, but even though Johnston took immediate command in the Department of Mississippi and East Louisiana after the fall of Vicksburg, it was impossible to reverse the effects that disaster.
Another bold initiative to wrest back the initiative in Tennessee occurred in the autumn of 1863 as strong reinforcements were transferred from Virginia to Tennessee. Despite tactical success at Chickamauga and strenuous efforts to regain eastern Tennessee, the endeavour was unsuccessful. It was proving impossible to hold the line at all the threatened points and simultaneously to form a concentration in the western theatre powerful enough to reverse Union progress decisively. Indeed, this offensive provoked a major shift in the Union High Command as Ulysses Simpson Grant was given the predominant command to save Chattanooga and the first truly unified Union command (the Military Division of the Mississippi) enabled the effective and coordinated application of force in 1864 and 1865 that had eluded the Confederates in 1862 and 1863.
The Military Division of the West was finally disbanded as an unworkable ideal in December 1863 after the fiasco at Chattanooga. The Georgia sector was defended by the Army of Tennessee which had been formed from the merged Army of Mississippi and the Army of Kentucky. Even when reinforced from Mississippi, it did not seem likely to halt the Union steamroller towards Atlanta.
The Department of Mississippi and East Louisiana, soon renamed the Department of Alabama and East Mississippi and later as the Department of Alabama, Mississippi, and Eastern Louisiana, provided the command structure in the western and Gulf sectors while the Department of Tennessee directed the primary eastern sector. Harassing operations continued in Mississippi and Alabama, but there were never enough troops to reverse the Union domination of the Mississippi valley and the majority of these forces were drawn back to the primary sector in northern Georgia once the Union began its advance towards Atlanta.
The next major evolution came after the fall of Atlanta. Incapable of regaining the city by a direct approach, the Confederates made one last attempt to reverse the Union invasion in the Georgia sector by another far-reaching offensive campaign. Renaming the Department of Tennessee as the Department of Tennessee and Georgia, General John Bell Hood inadvertently revealed the two diverging areas of geographical responsibility. He opted to attack the lengthy enemy lines of communications through Tennessee, and in so doing left Georgia almost defenceless. The audacity of the Union response, an unsupported march from Atlanta across Georgia to the Atlantic Ocean rather than a hasty retreat to guard its rear, was not foreseen.
The second coming of the Military Division of the West, led by General P G T Beauregard, intended to provide expert supervision to the inexperienced Hood and to coordinate in his support the Department of Western Kentucky, the Department of East Tennessee and West Virginia, the Department of Tennessee and Georgia and the Department of Alabama, Mississippi and Eastern Louisiana was another false start and it was abandoned after the crushing of Hood’s hopes and army at Nashville in December 1864.
The constituent Departments regained their autonomy after Beauregard’s Military Division was discontinued, but now they all lacked a substantial field force capable of resisting relentless Union progress through Georgia, the Carolinas, or Alabama. The defeat of the forts defending Mobile on the Gulf Coast was protracted but inevitable and the most strenuous efforts to create an Army of the South under Johnston from the remnants of armies and garrisons across Tennessee, Georgia and the Carolinas, resulted in the capacity to harass and annoy the advancing Union armies but not to halt them. The surrender of the Confederate Army in Virginia was followed within a month by the dissolution of the armies in North Carolina and Alabama.
The Confederates sought repeatedly to seize the strategic initiative in the western theatre, and made genuine attempts to achieve coordination and clarity of effort. However, shortage of resources, and the impossibility of defending all of the threatened avenues of invasion simultaneously, led to a proliferation of rival commands that were defeated in turn.
Eastern Theatre and Appalachian Theatre
The Eastern Theatre broadly covers the states of Virginia, Maryland, Pennsylvania, West Virginia, District of Columbia, and adjacent operational regions. Operations in the theatre were dominated by the fact that the two capitals at Washington, DC, and Richmond, Virginia, were barely one hundred miles apart. Virginia inevitably became a primary theatre of the conflict as each belligerent sought to threaten the other’s capital city while defending its own.
Each side had to provide for the defence of its capital, but the urgency was greater on the Union side, as loss of the capital would almost certainly prove to be a fatal blow to the Union cause. Therefore, large forces were tied down to occupy Washington’s extensive fortifications and to counter Confederate diversions and threats. Washington, DC also became the administrative nerve centre and the base for many significant logistical operations and this only added to its strategic significance. Until mid-1864, the sensitivity and vulnerability of the US capital meant that it was always strongly garrisoned and heavily fortified, and Confederate threats invariably provoked intense anxiety and impulsive reactions to ensure its defence. It was not until the suppression of Confederate forces in the Shenandoah Valley in late 1864 that the capital was finally considered secure.
The Union had to take the strategic initiative and attempted several overland advances towards Richmond, with occasional efforts made from the coast along the James River and Yorktown Peninsula. The Confederates responded aggressively and made diversionary advances and invasions towards Washington and across the Potomac River into Union territory. This required the Union to make continual adjustments to the military organisation north of the Potomac, which could raise short-term forces, forestall and react to raids, and provide security for the Northern hinterland.
Union forces quickly established bases on either side of the James River and in North Carolina and it became necessary to place garrisons to prevent further progress inland from the coasts. The proximity of Richmond and Petersburg to navigable waterways made their particularly vulnerable, and their loss would also cut lines of supply into central and northern Virginia. Confederate strategy focused from the start on protecting these locations, and making offensive movements or feints to divert Union forces from this critical area.
Both sides engaged continually in operations in the Shenandoah Valley and the mountainous region of western Virginia. The Valley was an important source of supplies for the Confederates and offered a covered line of advance into Union territory, an advantage that was exploited effectively in 1862, 1863, and 1864. The general south-westward orientation of the valley meant that any Union advance would gradually diverge and dissipate forces away from the main axis between Washington and Richmond.
Western Virginia was largely pro-Unionist and provided a base for Union operations towards prized natural resources and the vital East-West railroad line through eastern Tennessee and southwestern Virginia. The region was inaccessible to large forces and difficult either to occupy or defend but it constantly drew the attention of both sides. Difficult to conquer or garrison, there were many intense but short campaigns and raids. By late 1864 the Confederates had been so reduced that the Union was finally able to break out of the mountains into eastern Tennessee, southwestern Virginia and western North Carolina.
In the immediate crisis of the outbreak of war, short-lived organisations were improvised on the peripheries of Virginia. The earliest commands were established in western Virginia, the Yorktown peninsula, the Shenandoah Valley, the Norfolk Navy Yard, and most importantly south of the Potomac River. The largest single field force of the Confederacy was always stationed on the axis between Washington, DC, and Richmond. An aggressive strategy prompted bold invasions of Maryland in 1862 and 1864, and Pennsylvania in 1863, seeking to cut off or threaten the US capital. None was ultimately successful but they each caused alarm and provided occasional respite for Virginia.
The first year of the war saw the creation of many small, sometimes grandiosely titled field forces and territorial commands. Along these were the Forces in Norfolk which evolved into the Department of Norfolk; the Potomac Line which became the Department of Fredericksburg; the Forces in Richmond which became the Department of Richmond; western Virginia was served by the small Forces in the Kanawha Valley, the Army of the Kanawha, and the Army of the Northwest; the Department of Southwestern Virginia; the Hampton Line which became the Department of the Peninsula. The Shenandoah Valley always had its own local command, evolving from the Forces in Harper’s Ferry later renamed the Army of the Shenandoah and then the District and various permutations of the Army of the Northwest and the Army of the Valley.
The most important organisation was that facing the Union camps and forces gathering around Washington, DC. Beginning as the Department of Alexandria and the Forces in Alexandria or the Alexandria Line, the Confederates’ primary command grew into the Department of the Potomac, later renamed the Department Northern Virginia. This command and its famous Army, for almost its entire history and until the dissolution of the Confederacy was synonymous with the leadership of General Robert Edward Lee.
While Lee directed campaigns and the defence of the Confederacy’s most northerly frontier, the Department of Henrico managed the military and logistical functions of the capital itself, the Department of Richmond organised its garrison, and the Department of Southwestern Virginia (later Trans-Allegheny Department and Department of East Tennessee and West Virginia) protected the western fringe of the state. The need to coordinate operations of forces in southern Virginia and North Carolina resulted in a Department of North Carolina and Southern Virginia from September 1862 to February 1863 and again from May 1863, to protect the vital port of Wilmington and supply lines leading north into Petersburg, Virginia. Although these more minor organisations had some autonomy, they were usually subordinated to Lee’s dominant strategy.
Atlantic Coast Theatre
The Atlantic Coast Theatre broadly covers the states of Georgia, Florida, South Carolina, North Carolina, and adjacent operational regions in Alabama and Virginia. This theatre saw the first act of war at Charleston, South Carolina, when pro-Confederate forces opened fire on the Union garrison at Fort Sumter. This action was the first of many along the Atlantic Coasts as the Confederates attempted to protect their ports to import supplies and military equipment through the blockade.
The Confederates also needed to prevent the Union from establishing bases of operations for raids or advances into the interior of the nation. The US Navy gradually established outposts in Alabama, Florida, Georgia, South Carolina, and North Carolina. Some of these provided depots for the blockading fleets while others were set up to attack Confederate coastal fortifications. Others were occupied simply to deny the use of ports and coastal waters to Confederate maritime trade. The Confederates occasionally attacked the Union enclaves, but were rarely successful unless they could neutralise the Union naval forces supporting the garrisons ashore. In most cases, overwhelming Union naval force overpowered the Confederate defences; however, the important ports of Charleston, Wilmington, and Mobile, were not finally occupied until the final months of the war. Inevitably, as the Union threat could materialise at any one of several points – ports, fortifications, navigable rivers – the Confederates were forced to spread their garrisons thinly, concentrating only when clear evidence of an attack was identified at a particular point. Their military organisation was therefore complicated, with many low-level territorial organisations being created with responsibility for specific locations, and field forces on a comparatively small in scale.
Initially, the Confederates managed the defence of the Atlantic coast on a state by state basis. The Department of South Carolina was formed on 3 March 1861; the Department of Middle and Eastern Florida was formed on 20 August 1861 (western Florida was in a separate Department focused on the Gulf of Mexico coast); and the Department of Georgia was formed on 26 October 1861. These three Departments were combined to become Districts within a “super-Department” under General Robert Edward Lee on 5 November 1861. Lee’s Department of South Carolina, Georgia, and East Florida attempted to bring unity of command and singleness of purpose in states that were led by particularly ardent proponents of states’ rights.
After Lee’s departure, his extensive Department reverted to become more local Departments. On 13 March 1862, the Department of Middle and Eastern Florida, and the Department of South Carolina and Georgia, were formed in its place. This process was reversed in October 1862 when another high-ranking General, P G T Beauregard returned to command the reconstructed Department of South Carolina, Georgia, and Florida. Once again, the constituent parts of the Department were allocated to Districts and smaller subdivisions to organise its scattered garrisons. The Department remained in operation, undergoing a gradual segmentation until the final surrender on 26 April 1865, by which time its field forces had been largely dispersed and all of its major cities occupied or neutralised by Union land or naval forces. Although superficially a complex organisation, the constituent parts of the Department related to ports and access points along the coast, undergoing adjustment as the Union points of attack shifted. Its ultimate collapse was achieved not so much by incursion from the coast but by the overland march across Georgia conducted by Union Major-General William Tecumseh Sherman in late 1864. Although the primary ports had been skilfully and determinedly defended, Sherman’s March to the Sea, and Sherman’s irresistible campaign through the Carolinas in early 1865, exposed the vulnerability of the region when exposed to large land forces.
The coasts of North Carolina were among the first to be seriously threatened. The navigable waters around Roanoke and the Pamlico quickly attracted some of the first major amphibious operations of the Union, in Spring 1862. The Union soon secured bases at New Bern and Elizabeth City, to supplement the valuable harbour of Port Royal, captured at the end of 1861. The Department of North Carolina was created on 22 April 1861 with a primary goal of defending its coastal waters. Its subdivisions related directly to fortifications and defences. The most important position was immediately identified as Wilmington on the Cape Fear and the port was protected by Fort Fisher at the mouth of the Cape Fear right until early 1865. Its fall severed the last available blockade running route and precipitated the final collapse of the Confederate armies.
The need for coordinated operations with forces in southern Virginia increasingly required an amalgamation of the North Carolina organisations with those in Southern Virginia. The Department of North Carolina and Southern Virginia existed from 19 September 1862 until 26 February 1863. It reverted to the separate Department of North Carolina and Department of Southern Virginia from 26 February 1863 to 28 May 1863 but was then reconstituted as the Department of North Carolina and Southern Virginia on 28 May 1863. By the end of 1864, it managed the vital defence of Wilmington and the supply lines leading north into Petersburg, Virginia. This Department remained in existence until the final surrender on 26 April 1865.
The Trans-Mississippi Theatre broadly covers the states of Texas, Arkansas, Missouri, western Louisiana, the Indian Territory, Arizona Territory, New Mexico Territory, and adjacent operational regions.
The largest Confederate state west of the Mississippi was Texas and its military defences quickly took shape. There were three initial objectives: to provide a base of operations to extend Confederate influence into the western territories; to secure the coastal ports against enemy incursion and to retain open ports against the blockade; and thirdly, being broadly immune to overland invasion, to provide reinforcements and supplies for the more exposed states of Arkansas and Louisiana. The Department of Texas was established on the outbreak of war on 11 April 1861 and satellite districts and sub-districts were established quickly to manage its far flung territory and evict its Federal garrisons. These coalesced around Galveston, Pass Cavallo, Houston, the Rio Grande, and the Western and Eastern Districts of the state.
Control of the Indian Territory was continually disputed with the Union. It was initially treated as an autonomous military region but on 22nd November 1861, it became the Department of the Indian Territory. The Arizona Territory operated as an autonomous military District from 1 October 1861.
The remainder of the Trans-Mississippi theatre was treated initially in a way similar to the Union, namely, to treat the Mississippi River not as a border but as the centre of the military geography. The Western Department established on 25 June 1861 brought all the territory north of the 31st parallel, up the Mississippi River and east of the Tennessee River. This gave at least theoretical unity of command of the decisive area where the Mississippi, Missouri, Ohio, and Tennessee converged. The District of Upper Arkansas and the Forces in Missouri took responsibility west of the Mississippi, although matters in Missouri were confused. By 4 July 1861, the Western Department had been extended to include much of Alabama, the Mississippi River counties of Arkansas and Mississippi and Louisiana north and east of the White and Black Rivers. The Western Army was established unofficially on 4 August 1861 to direct the forces west of the Mississippi.
In response to the obvious need to coordinate operations either side of the Mississippi, the growth of the Western Department continued inexorably. On 10 September 1861, it was extended to include Kentucky, Tennessee, Missouri, Arkansas, and the Indian Territory. The highly regarded General Albert Sidney Johnston assumed command but his attention was necessarily focused much mor intently on developments in Kentucky and Tennessee.
The Indian Territory was unmanageably distant and on 22 November 1861 the Department of the Indian Territory was detached again to act independently of the Western Department. The same obstacles of distance and diverging priorities forced further changes in January 1862. The District of Upper Arkansas was discontinued, and became part of a new Trans-Mississippi District which straddled the river and was subordinated to the Western Department. Soon afterwards, the Western Army was discontinued, and incorporated into a new Army of the West, which was being considered for transfer from the less urgent operations west of the Mississippi to the eastern side. The Trans-Mississippi District existed from January 1862 until 20 August 1862, and included Louisiana north of the Red River, the Indian Territory, and the states of Arkansas and most of Missouri.
The most significant and far-reaching organisational decision was made on 26 May 1862, in an attempt to rationalise this unwieldy structure. The new Trans-Mississippi Department was established with the Mississippi River as its obvious eastern border and with responsibility for everything west of it. That separation allowed the Western Department to manage affairs east of the river without distraction. The Department remained in existence until the end of hostilities and was the last major Confederate command to surrender. Although internal adjustments were made in response to the evolving Union threats and invasions, the Department remained broadly intact and unchanged. It became almost synonymous with its commander, Edmund Kirby Smith, after he took command from 14 January 1863; so much so that it even acquired the nickname of “Kirby-Smithdom”.
The Trans-Mississippi Department took charge of Texas, the Indian Territory, and Arkansas, and acquired the parts of Louisiana west of the Mississippi. Texas continued to be managed as a set of smaller territorial commands, while Arkansas, Arizona, and the Indian Territory became separate Districts. The Trans-Mississippi District – in fact, more of an “along the Mississippi” district – had existed from January 1862 until 20 August 1862, and included Louisiana north of the Red River, the Indian Territory, and the states of Arkansas and most of Missouri. It was discontinued on 20 August 1862 when a short-lived District of Missouri was formed. At the same time, western Louisiana became a separate District, and the District of Texas was also formed to direct its subordinate territories.
By November 1862, the far western territories were irretrievably lost from Confederate control and the District of Texas took over the westernmost regions of the Confederacy as the District of Texas, New Mexico, and Arizona. The Indian Territory came under the District of Arkansas in March 1863.
The Trans-Mississippi struggled to raise, equip, and retain large field forces in its comparatively under-developed territory. The Army of the West had long since been sent east of the Mississippi and strenuous efforts were made to raise a new force for the Trans-Mississippi. Known from September 1862 as the Southwest Army, its heterogeneous parts were dubbed the Trans-Mississippi Army in February 1863 after Smith’s arrival. The immensity of its operational area and difficulty of supply, meant that the army never operated as a single whole, but its various segments were deployed as necessary to Arkansas, the Texas coast, western Louisiana, and even in Missouri.
The same difficulties that hampered Confederate operations, also made it difficult for the Union to penetrate far into the interior of the region. The far western territories were over-run during 1862, Arkansas was occupied slowly in stages, and a defensive cordon was established to protect Union-occupied New Orleans from the west. However, Union attempts to advance further inland, whether from the Texas coast, overland from Arkansas, up the Red River, or through western Louisiana, were repelled by skilful counter-attacks. The ambitious Confederate invasion of Missouri late in 1864 proved to be an ineffectual swan-song.
This tripartite structure of Districts in Arkansas, western Louisiana, and Texas (with the western territories) changed little from August 1862 until early 1865, by which time little or no thought could be given to expansive operations. Nor were such operations required as the Union had largely adopted a passive posture west of the Mississippi after securing Arkansas, the Mississippi valley, and the majority of the Texan ports.
In April 1865, the District of Arkansas and the District of Western Louisiana were discontinued and incorporated into a new District of Arkansas and West Louisiana. This final adjustment pre-dated by just over a month the surrender of the entire Trans-Mississippi Department on 26 May 1865.