Army group An army group is a military organization consisting of several field armies , which is self - sufficient for indefinite periods . It is usually responsible for a particular geographic area . An army group is the largest field organization handled by a single commander — usually a full General or Field Marshal — and it generally includes between 400 , 000 and 1 , 000 , 000 soldiers . In the Polish Armed Forces and former Soviet Red Army an army group was known as a Front . The equivalent of an army group in the Imperial Japanese Army ( IJA ) was an Area Army ( ) . Army groups may be multi - national formations . For example , during World War II , the Southern Group of Armies ( also known as the U . S . 6th Army Group ) comprised the U . S . Seventh Army and the French First Army ; the 21st Army Group comprised the British Second Army , the Canadian First Army and the US Ninth Army . In U . S . Army usage , the number of an army group is expressed in Arabic numerals ( e . g . , " 12th Army Group " ) , while the number of an army is spelled out ( e . g . , " Third Army " ) . World War II . China . A Chinese " army group " was usually equivalent in numbers only to a field army in the terminology of other countries . On 16 May 1940 , Zhang Zizhong , commander of the 33rd Army Group was killed in action in Hubei province . He was the highest ranking Chinese officer to be killed in the war . Germany . The German Army was organized into army groups ( " Heeresgruppen " ) . ( See List of German Army Groups in WWII . ) Some of these army groups were multinational , containing armies from several Axis countries . For example Army Group Africa contained both German and Italian corps . Japan . During World War II there were six General Armies : In April 1945 , the " Boei So - Shireibu " ( translated as " General Defense Command " or " Home Defense General Headquarters " and similar names ) was split into three General Armies : By August 1945 , these comprised two million personnel in 55 divisions and numerous smaller independent units . After the surrender of Japan , the IJA was dissolved , except for the " Dai - Ichi So - Gun " , which existed until 30 November 1945 as the 1st Demobilization Headquarters . Soviet Union . The Soviet Army was organized into Front s ( " фронт pl . фронты " ) which were often as large as an army group . ( See List of Soviet fronts in World War II . ) Some of the Fronts contained Allied formations raised in exile . For example , the Polish First Army was part of the 1st Belorussian Front . Western Allies . Mediterranean . Allied Forces Headquarters ( AFHQ ) in the Mediterranean theater also had operational command of the 15th Army Group ( a multi - national army group ) fighting in Italy . North West Europe . In April 1943 , the previously informal Western Allied collaboration in the North West Europe was strengthened by the establishment in London of a formal planning headquarters called Chief of Staff Supreme Allied Command ( COSSAC ) . In February 1944 , this headquarters was replaced by the final interallied headquarters for the Theater — Supreme Headquarters Allied Expeditionary Forces ( SHAEF ) . SHAEF was the operational command , headed by General Dwight D . Eisenhower , that planned the invasion and issued operational commands once the invasion took place . Eisenhower also became ( in January 1944 ) the commanding general of the European Theater of Operations United States Army ( ETOUSA ) that was responsible for the administration of American forces in the theater ( dealing with matters such as pay and recreation ) . The staff organizations of SHAEF and ETOUSA were distinct . As a rule , each headquarters had its own staff sections manned by separate personnel . The staff organization in SHAEF was headed by the Chief of Staff and had as an important officer the Secretary of the General Staff . The G - 2 and G - 3 divisions of SHAEF , which comprise a portion of this accession , functioned according to the United States War Department General Staff pattern . SHAEF had operational control over three inter - Allied ground commands known as Army Groups . The initial two were the 21st Army Group and the 12th Army Group ( originally the U . S . 1st Army Group or FUSAG ) , and in September 1944 , operational command of the Sixth Army Group ( which had landed in the south of France during Operation Dragoon ) passed from Allied Force Headquarters ( AFHQ ) to SHAEF . As part of the pre - invasion deception plan called Operation Quicksilver , the original FUSAG was renamed 12th Army Group , and " FUSAG " continued as a notional army group threatening to invade France across the Straits of Dover . South East Asia . South East Asia Command ( SEAC ) in the South - East Asian theater had operational command of the British 11th Army Group that was later reorganised and redesignated Allied Land Forces South East Asia ( ALFSEA ) . Like most other Western Allied army groups , ALFSEA co - ordinated a mixture of Allied forces from several nations . NATO ' Army Groups ' . During the Cold War , NATO land forces in what was designated the Central Region ( most of the Federal Republic of Germany ) would have been commanded in wartime by two ' Army Groups ' . Under Allied Forces Central Europe and alongside air force elements , the two Army Groups would have been responsible for the defence of Germany against any Soviet / Warsaw Pact invasion . These two Principal Subordinate Commanders ( PSCs ) had only limited peacetime authorities , and issues such as training , doctrine , logistics , and rules of engagement ( ROE ) were largely a national , rather than Alliance , responsibility . The two formations were the ' Northern Army Group ' ( NORTHAG ) and the ' Central Army Group ' ( CENTAG ) . By World War II and previous standards these two formations were only armies , as they contained four corps each . NORTHAG consisted , from north to south , of I Netherlands Corps ( I ( NE ) Corps ) , I German Corps ( I ( GE ) Corps ) , I ( BR ) Corps , and I Belgian Corps ( I ( BE ) Corps ) . Its commander was the British commander of the British Army of the Rhine ( BAOR ) . CENTAG consisted , from north to south , of III ( GE ) Corps , V US Corps , VII ( US ) Corps , and II ( GE ) Corps in the extreme south of the Federal Republic of Germany . The commander of the United States Army Europe commanded CENTAG . In November 1991 , the NATO heads of state and government adopted the " New Strategic Concept " at the NATO Summit in Rome . This new conceptual orientation led , among other things , to fundamental changes both in the force and integrated command structure . Structural changes began in June 1993 , when HQ Central Army Group ( CENTAG ) at Heidelberg and Northern Army Group ( NORTHAG ) at Mönchengladbach , GE were deactivated and replaced by Headquarters Allied Land Forces Central Europe ( LANDCENT ) , which was activated at Heidelberg on 1 July 1993 .