Operational formation In many armies, a corps is a battlefield formation composed of two or more
divisions, and typically commanded by a
lieutenant general. During
World War I and
World War II, due to the large scale of combat, multiple corps were combined into
armies which then formed into
army groups. In Western armies with numbered corps, the number is often indicated in
Roman numerals (e.g.,
VII Corps).
Australia and New Zealand The
Australian and New Zealand Army Corps was raised in 1914, consisting of Australian and New Zealand troops, who went on to fight at
Gallipoli in 1915. In early 1916, the original corps was reorganized and two corps were raised:
I ANZAC Corps and
II ANZAC Corps. In the later stages of World War I, the five infantry divisions of the
First Australian Imperial Force (AIF)—consisting entirely of personnel who had volunteered for service overseas—were united as the
Australian Corps, on the
Western Front, under Lieutenant General Sir
John Monash. During World War II, the
Australian I Corps was formed to co-ordinate three
Second Australian Imperial Force (2nd AIF) units: the
6th,
7th and
9th Divisions, as well as other Allied units on some occasions, in the
North African campaign and
Greek campaign. Following the commencement of the
Pacific War, there was a phased withdrawal of I Corps to Australia, and the transfer of its headquarters to the
Brisbane area, to control Allied army units in
Queensland and northern
New South Wales (NSW).
II Corps was also formed, with
Militia units, to defend south-eastern Australia, and
III Corps controlled land forces in
Western Australia. Sub-corps formations controlled Allied land forces in the remainder of Australia. I Corps headquarters was later assigned control of the
New Guinea campaign. In early 1945, when I Corps was assigned the task of
re-taking Borneo, II Corps took over in New Guinea.
Canada Canada first fielded a corps-sized formation in the First World War; the
Canadian Corps was unique in that its composition did not change from inception to the war's end, in contrast to British corps in France and Flanders. The Canadian Corps consisted of four Canadian divisions. After the Armistice, the peacetime
Canadian militia was nominally organized into corps and divisions but no full-time formations larger than a battalion were ever trained or exercised. Early in the Second World War, Canada's contribution to the British-French forces fighting the Germans was limited to a single division. After the fall of France in June 1940, a second division moved to England, coming under command of a Canadian corps headquarters. This corps was renamed
I Canadian Corps as a second corps headquarters was established in the UK, with the eventual formation of five Canadian divisions in England. I Canadian Corps eventually fought in Italy,
II Canadian Corps in northwest Europe, and the two were reunited in early 1945. After the formations were disbanded after VE Day, Canada has never subsequently organized a corps headquarters.
Royal Canadian Army Cadets: A corps size in the RCAC is different everywhere, depending on the size. The commanding officer can be a
captain (Previously, Commanding Officers of a large corps could have been a Major, but that capability has been removed with the creation of CJCR Group Order 5511-1)
China The
National Revolutionary Army (NRA) corps () was a type of military organization used by the
Chinese Republic, and usually exercised command over two to three
NRA divisions and often a number of independent
brigades or
regiments and supporting units. The Chinese Republic had 133 corps during the
Second Sino-Japanese War. After losses in the early part of the war, under the 1938 reforms, the remaining scarce artillery and the other support formations were withdrawn from the division and was held at corps, or army level or higher. The corps became the basic tactical unit of the NRA having strength nearly equivalent to an allied
division. The modern
People's Liberation Army Ground Force group army () is the closest equivalent of a corps. After the military reforms of the early 2010s, a typical PLA group army consists of six combined arms brigades, plus additional artillery, air defence, engineering, sustainment, special operations and army aviation assets. Each formation contains approximately 30,000 combat troops and several thousands more supporting personnel.
France The
French Imperial Army under Napoleon used corps-sized formations () as the first formal combined-arms groupings of
divisions with reasonably stable manning and equipment establishments. Napoleon first used the in 1805. The use of the was a military innovation that provided Napoleon with a significant battlefield advantage in the early phases of the
Napoleonic Wars. The corps was designed to be an independent military group containing cavalry, artillery and infantry, and capable of defending against a numerically superior foe. This allowed Napoleon to mass the bulk of his forces to effect a penetration into a weak section of enemy lines without risking his own communications or flank. This innovation stimulated other European powers to adopt similar military structures. The corps has remained an echelon of French Army organization to the modern day.
Germany As fixed military formation already in peace-time it was used almost in all European armies after
Battle of Ulm in 1805. In Prussia it was introduced by
Order of His Majesty () from 5 November 1816, in order to strengthen the readiness to war.
India The
Indian Army has
14 corps, each commanded by a
general officer commanding (GOC), known as the corps commander, who holds the rank of
lieutenant general. Each corps is composed of three or four divisions. There are three types of corps in the Indian Army: strike, holding and mixed. The corps HQ is the highest field formation in the army.
Pakistan The
Pakistan Army has nine manoeuvre corps, each commanded by a
lieutenant general. Each corps is composed of at least two divisions. The corps HQ is the highest field formation in the army.
Poland (1938–1939) The
Polish Armed Forces used
independent operational groups in the place of the corps before and during
World War II. An example would be
Independent Operational Group Polesie. The groups, as the name indicates, were more flexible and showed greater capacity to absorb and integrate elements of broken units over a period of just a couple days and keep cohesion during the
September Campaign than more traditional army units such as divisions, regiments, or even brigades.
Russia In Russia (then the
Empire), corps were officially introduced in 1810, under Emperor
Alexander I, when 5 corps of different compositions were formed from all
branches of the military.
United Kingdom Wellington formed a in 1815 for commanding his mixed allied force of four divisions against Napoleon. When the British Army was expanded from an expeditionary force in the First World War, corps were created to manage the large numbers of divisions. The
British corps in World War I included 23 infantry corps and a few mounted corps. The word was adopted for other special formations such as the
Officers Training Corps. Military training of teenage boys is undertaken at secondary schools through the
Combined Cadet Force, in which participation was compulsory at some schools in the 1950s. Schoolboy jargon called the CCF simply "Corps". The
British Army still has a corps headquarters for operational control of forces.
I Corps of the
British Army of the Rhine was redesignated the
Allied Rapid Reaction Corps in 1994. It is no longer a purely British formation, although the UK is the "framework nation" and provides most of the staff for the headquarters. A purely national Corps headquarters could be quickly reconstituted if necessary. It took command of the International Security Assistance Force in Afghanistan on 4 May 2006. Previously, it was deployed as the headquarters commanding land forces during the
Kosovo War in 1999 and also saw service in
Bosnia and Herzegovina, commanding the initial stages of the
IFOR deployment prior to that in 1996. Otherwise, the only time a British corps headquarters has been operationally deployed since 1945 was
II Corps during the
Suez Crisis.
United States Lloyd Austin, returns home from
Operation Iraqi Freedom in 2009 The structure of a field corps in the
United States Army is not permanent. On the battlefield, the corps is the highest level of the forces that is concerned with actual combat and operational deployment. Higher levels of command are concerned with administration rather than operations, at least under current doctrine. The corps provides operational direction for the forces under its command. As of 2014, the active field corps in the US Army are
I Corps,
III Corps, and
XVIII Airborne Corps; their lineages derive from three of the corps formed during World War I (I and III Corps) and World War II (XVIII Airborne Corps). On 12 February 2020, it was announced that the Army was reactivating
V Corps to bolster the presence of US forces in Europe.
American Civil War The first field corps in the
United States Army were legalized during the
American Civil War by an act of Congress on 17 July 1862, although the term had been used previously to refer to any large portion of the army. Major General
George B. McClellan, for example, planned to organize the
Army of the Potomac into corps of two or more
divisions and about 25,000 soldiers. However, he delayed doing so, partly for lack of experienced officers, and partly for political reasons, until March 1862 when
President Lincoln ordered their creation. The exact composition of a corps in the
Union Army varied during the war, though it usually consisted of two to six divisions (three on average) for approximately 36,000 soldiers. After
Ambrose Burnside was given command of the Army of the Potomac in November 1862, he reorganized it into three "grand divisions" of two corps and a cavalry division each, but this structure was abolished when
Joseph Hooker took over February 1863. This also led to the creation of a dedicated
Cavalry Corps of three divisions and
horse artillery assigned to the corps headquarters. In the early years of the war,
field artillery was either part of an artillery reserve under direct army control or assigned to individual divisions. However, after the
Battle of Chancellorsville the divisional artillery was placed under corps control, with each corps assigned a
brigade of four to six
batteries commanded by the senior-most artillery officer. In general, the other field armies tended to model their organization after the Army of the Potomac, including the gradual development of corps. Corps were commanded by major generals because Congress refused to promote officers past that grade (with the exception of
Ulysses S. Grant to
lieutenant general in 1864). an assistant
adjutant general, a
quartermaster, an assistant
inspector general, a commissary of subsistence, an ordnance officer (all with the rank of
lieutenant colonel), and a medical director. However, there were no dedicated
combat service support formations as part of the corps. This meant that either civilian workers had to be hired or line soldiers detailed from their units to carry out the necessary tasks. Initially, corps were numbered in relation to their field army, such as I Army Corps, Army of the Potomac. After a while these numerical designations became unique to each corps regardless of the army to which they were assigned. Two of these saw action as a unit: the Fifth in Cuba and the Eighth in the Philippines; elements of the
First,
Fourth, and
Seventh made up the invasion force for Puerto Rico (the Second,
Third, and Seventh provided replacements and occupation troops in Cuba, while the
Sixth was never organized). The corps headquarters were disbanded during the months following the signing of the peace treaty (with the exception of the Eighth Army Corps, which remained active until 1900 due to the eruption of the
Philippine–American War), and like the corps of the Civil War, their lineage ends at that point.
World Wars I and II During World War I, the
American Expeditionary Forces (AEF) adopted the common European usage of designating field corps by
Roman numerals. Several "
corps areas" were designated under the authority of the
National Defense Act of 1920, but played little role until the Army's buildup for World War II. While some of the lower numbered corps were used for various exercises, the inter-war years corps served mostly as a pool of units. During that war, the Marine Corps organized corps headquarters for the first time, the
I Marine (later
III Amphibious Corps) and
V Amphibious Corps. The Army ultimately designated 25 field corps (I–XVI, XVIII–XXIV, XXXVI, and
I Armored Corps) during World War II.
Cold War and 21st century After the
Korean War, the Army and Marines diverged in their approach to the concept of the field corps. The Army continued to group its divisions into traditional corps organizations in the Continental United States (CONUS), West Germany (
V Corps and
VII Corps), and South Korea (I Corps). However, during the
Vietnam War, the Army designated its corps-level headquarters in South Vietnam as
I Field Force and
II Field Force to avoid confusion with the
ARVN corps areas. As of July 2016, the Army deactivated all corps headquarters save three CONUS based corps (
I Corps – Washington,
III Corps - Texas, and
XVIII Airborne Corps – North Carolina). In the 1960s, the Marine Corps activated the
I Marine Expeditionary Force (I MEF) on Okinawa (based in California since 1971) and
II Marine Expeditionary Force (II MEF) in North Carolina, and re-activated the III Amphibious Corps (which had been deactivated in 1946) as
III Marine Expeditionary Force (III MEF) in South Vietnam (re-deployed to Okinawa in 1971). In 1965, all three MEFs were subsequently re-designated as Marine amphibious forces or MAFs, and in 1988 all three Marine Corps corps-level commands were again re-designated as
Marine expeditionary forces (MEF). The MEF had evolved into a self-contained, corps-level,
Marine air–ground task force (MAGTF) consisting of a MEF headquarters group, a Marine division, a Marine aircraft wing, and a force service support group (re-designated as Marine logistics group in 2005).
Soviet Union The pre–
World War II Red Army of the former
USSR had
rifle corps much like in the Western sense with approximately three divisions to a corps. However, after the war started, the recently purged Soviet senior command (
Stavka) structure was apparently unable to handle the formations, and the armies and corps were integrated. Rifle corps were re-established during the war after
Red Army commanders had gained experience handling larger formations. Before and during World War II, however, Soviet armoured units were organized into corps. The pre-war
mechanized corps were made up of divisions. In the reorganizations, these "corps" were reorganized into tank
brigades and support units, with no division structure. Owing to this, they are sometimes, informally, referred to as "brigade buckets". After the war, the tank and mechanized corps were re-rated as divisions. During the reforms of 1956–58, most of the corps were again disbanded to create the new combined arms and tank armies. A few corps were nevertheless retained. The Vyborg and Archangel Corps of the
Leningrad Military District were smaller armies with three low-readiness motorized rifle divisions each. In the 1980s "Unified Corps" on the brigade pattern were created in the
Belorussian Military District (Western TVD/Strategic Direction) and the
48th Separate Guards Army Corps in the
Transbaikal Military District, but abandoned after a few years. The
Soviet Air Forces used ground terminology for its formations down to squadron level. As intermediates between the
aviation division and the air army were corps—these also had three air divisions each.
Air Defence Corps An Air Defence Corps ('KPVO') is an operational-tactical formation (in the past - the highest tactical formation) of the former
Soviet Air Defence Forces and now
Russian Air Defence Forces/Aerospace Forces. The purpose of the such a corps is to protect important administrative, industrial and economic centers and regions of the country, groupings of troops (forces) and military facilities within the established limits of responsibility against air strikes. In organizational terms, an air defence corps is part of the district (or a separate army) of the Air Defence Forces. Also some air defence corps were separate. On the basis of individual corps,
air defence zones or
air defence corps areas could be created. The first
KPVO were created in February 1938 for the air defence of
Moscow,
Leningrad and
Baku (respectively 1st, 2nd and 3rd) based on anti-aircraft artillery divisions and air defence brigade (
3rd KPVO). The staff of the
KPVO included: 4-6 anti-aircraft artillery regiments, 1 anti-aircraft machine-gun regiment, 1 searchlight regiment (or battalion), 1-2 regiments (or divisions)
barrage balloons, 1- 2 regiments (or battalions) of visual observation, warning and communications (
VNOS), and a separate communications battalion. From September 1938 to November 1940, the
KPVO also included 1-2 regiments (battalions) of local air defence. During the Great Patriotic War from November 1941 to April 1944 the air defence corps were renamed into air defence corps areas (such as the
Stalingrad Corps Region). The corps districts included up to 9 anti-aircraft artillery regiments and 14 separate anti-aircraft artillery battalions, up to 3 anti-aircraft machine-gun regiments, 1 searchlight regiment, 1 regiment (or division) of barrage balloons, up to 4 regiments (or separate battalions) VNOS, and a communications regiment (or a separate battalion). In 1945, air defence corps could include 1 anti-aircraft artillery brigade or division. Air defence fighters operating within the limits of responsibility of the
KPVO was transferred to the corps. By the end of the war, there were 14
KPVO in the Active Army, of which 5 corps continued to carry out the tasks assigned to them even after the war, and the rest of the corps were disbanded. In July 1947, all
KPVO were renamed anti-aircraft artillery corps. In January 1949, part of these corps was reorganized into
air defence areas. From December 1948 to January 1949, all anti-aircraft artillery corps were disbanded. In June 1954, for the defense of the main industrial and economic centers and regions of the USSR, 10 air defence corps were re-created. At the same time, in addition to anti-aircraft artillery formations, fighter aviation regiments and divisions were included in the corps. Since the late 1950s, anti-aircraft artillery units have been replaced by anti-aircraft missile formations and formations of radio engineering troops. Searchlight and barrage balloon units were also abolished. In the
Warsaw Pact countries, groupings similar to the Soviet air defence corps were also created. In June–July 1960, all
KPVO were enlarged and consisted of: anti-aircraft missile regiments and brigades, air defense fighter regiments, radio engineering regiments and brigades, separate
electronic warfare battalions, regiments and battalions of communications and logistics institutions.
Administrative corps In many English-speaking countries and other countries influenced by British military traditions, a corps is also a grouping of personnel by common function, also known as an
arm,
service,
mustering or
branch.
Britain In the British Army, an administrative corps performs much the same role – for personnel that otherwise lack them – as a
ceremonial regiment. An administrative corps therefore has its own
cap badge,
stable belt, and other insignia and traditions. •
Intelligence Corps •
RAF Regiment •
Royal Logistic Corps •
Corps of Royal Marines •
Royal Corps of Signals In some cases, the term corps is also used informally, for looser groupings of independent regiments and other units – and without many or any unifying
regalia,
military traditions or other accoutrements – such as the
Royal Armoured Corps or the "Corps of Infantry".
Australia In Australia, soldiers belong foremost to a corps which defines a common function or employment across the army. The
Australian Army has a system of coloured lanyards, which each identify a soldier as part of a specific corps (or sometimes individual battalion). This lanyard is a woven piece of cord which is worn on ceremonial uniforms and dates back to the issue of clasp knives in the early 20th century which were secured to the uniform by a length of cord. If a soldier is posted to a unit outside of their parent corps, except in some circumstances the soldier continues to wear the hat badge and lanyard of their corps (e.g. a clerk posted to an infantry battalion would wear the hat badge of the Royal Australian Army Ordnance Corps but would wear the lanyard of the battalion they are posted to).
Canada In
Canada, with the integration of the Canadian Army into the
Canadian Forces, the British corps model was replaced with
personnel branches, defined in
Canadian Forces Administrative Orders (CFAOs) as "...cohesive professional groups...based on similarity of military roles, customs and traditions."
CFAO 2-10) However, the Armour Branch continued to use the title
Royal Canadian Armoured Corps, the Infantry Branch continued to use the
Royal Canadian Infantry Corps designation, and the Artillery Branch uses the term
Royal Regiment of Canadian Artillery. When the Army,
Royal Canadian Navy, and
Royal Canadian Air Force were merged in 1968 to form the Canadian Forces, the
Royal Canadian Dental Corps and
Royal Canadian Army Medical Corps were deactivated and merged with their Naval and Air Force counterparts to form the
Dental Branch (Canadian Forces) and the
Canadian Forces Medical Service of the Canadian Forces Health Services Group (CF H Svcs Gp). The
Royal Canadian Army Service Corps transport and supply elements were combined with the
Royal Canadian Ordnance Corps to form the
Logistics Branch The
Royal Canadian Army Service Corps clerical trades were merged with the
Royal Canadian Army Pay Corps and the
Royal Canadian Postal Corps to form the Administration Branch (later merged with the
Logistics Branch) Other "corps", included:
Canadian Engineer Corps,
Signalling Corps,
Corps of Guides,
Canadian Women's Army Corps,
Royal Canadian Army Veterinary Corps,
Canadian Forestry Corps,
Canadian Provost Corps and
Canadian Intelligence Corps.
India Administrative corps in the
Indian Army include: •
Army Armoured Corps •
Army Aviation Corps • Army Dental Corps •
Army Education Corps •
Army Medical Corps •
Army Ordnance Corps •
Army Postal Service Corps •
Army Service Corps •
Corps of Army Air Defence •
Corps of Electronics and Mechanical Engineers •
Corps of Engineers •
Corps of Military Police •
Corps of Signals •
Defence Security Corps •
Intelligence Corps •
Pioneer Corps •
Remount and Veterinary Corps New Zealand In New Zealand, soldiers belong foremost to a corps which defines a common function or employment across the army. A corps in the
New Zealand Army is an administrative group that comprises members of similar work functions. If a soldier is posted to a unit outside of their parent corps, except in some circumstances the soldier continues to wear the hat badge of their corps (e.g. a
supply technician posted to an infantry battalion would wear the hat badge of the
Royal New Zealand Army Logistic Regiment.
United States The
Department of Defense; the
Department of Transportation; and the
United States Department of Health and Human Services use
corps administratively in several ways. 1) In the title of the
United States Marine Corps,
Corps is used as a service-branch designator, in much the same way as
Force and
Guard are used for the
US Air Force and
US Coast Guard. 2) The
US Army (all
components;
Regular Army,
Army Reserve, and
Army National Guard) uses administrative
corps, also known as
army branches, to group personnel with a common function. These include the
Acquisition Corps,
Adjutant General's Corps,
Chaplain Corps,
Chemical Corps,
Civil Affairs Corps,
Cyber Corps,
Dental Corps*,
Corps of Engineers,
Finance Corps,
Judge Advocate General's Corps,
Logistics Corps,
Medical Corps*,
Medical Service Corps*,
Medical Specialist Corps*,
Military Intelligence Corps,
Military Police Corps,
Nurse Corps*,
Ordnance Corps,
Psychological Operations Corps,
Quartermaster Corps,
Signal Corps,
Transportation Corps, and
Veterinary Corps.* Each of these corps is also considered a
regiment for purposes of: "... affiliation, ... loyalty and commitment, ... sense of belonging, ... unit esprit, and ... war fighting ethos." However, these regiments have no tactical function. The six corps (annotated by an asterisk above after each applicable corps' name) of the
Army Medical Department (AMEDD) are included in the AMEDD Regiment . 3)
US Navy officers who are not
line officers (i.e., those who exercise general command authority and are eligible for operational command positions, as opposed to officers who normally exercise authority only within their own specialty) are commissioned into various
Staff Corps. These officers are specialists in career fields that are professions unto themselves, such as ministers, civil engineers, architects, dentists, lawyers, physicians, healthcare administrators, healthcare scientists, clinical care providers, nurses, financial managers, and logistics and supply specialists. These
corps include the
Chaplain Corps,
Civil Engineer Corps,
Dental Corps*,
Judge Advocate General's Corps,
Medical Corps*,
Medical Service Corps*,
Nurse Corps*, and the
Supply Corps. The Navy also has a
Hospital Corps consisting of enlisted medical technicians. The Hospital Corps, along with the four Navy health services corps listed above (indicated by asterisk), is one of the five corps of the Navy
Bureau of Medicine and Surgery. 4) The US Air Force uses the title
corps to designate several non-tactical organizations. These corps include five distinct health services corps of the
United States Air Force Medical Service (AFMS). The AFMS corps are the
Biomedical Sciences Corps,
Dental Corps,
Medical Corps,
Medical Service Corps, and
Nurse Corps. The Air Force also has its own
Chaplain Corps and
Judge Advocate General's Corps. 5) In the US Armed Forces, the term
corps is also used in a general sense to mean the collective membership of a specified military body. Those uses include: the
Officer Corps and
Noncommissioned Officer Corps (NCO Corps) of the armed forces, either collectively or individually by branch of service; the
United States Corps of Cadets at the
United States Military Academy and the
United States Coast Guard Corps of Cadets of the
United States Coast Guard Academy; the overall program title and aggregate collection of cadets and midshipmen enrolled in the
Reserve Officer Training Corps (ROTC) of the several services (i.e.,
Army ROTC,
Navy ROTC, and
Air Force ROTC), as well as the cadet organizations of the six federally recognized
United States Senior Military Colleges (
The Citadel,
Norwich University,
Texas A&M University, the
University of North Georgia, the
Virginia Military Institute, and
Virginia Polytechnic Institute and State University); and the members of the
Naval Sea Cadet Corps. ==Non-military use==