21st Army Group
Shoulder flash of the 21st Army Group
Active	July 1943 to August 1945
Allegiance	United Kingdom
Role	Army Group headquarters
Size	2 Field Armies
Part of	Supreme Headquarters Allied Expeditionary Force (SHAEF)
Commanders
Notable commanders	Bernard Paget Bernard Montgomery

The 21st Army Group was a British headquarters formation consisting primarily of British and Canadian forces. The Army Group was an important Allied force in the European Theatre of World War II. It was established in London during July 1943 under the command of Supreme Headquarters Allied Expeditionary Force (SHAEF) and was assigned to Operation Overlord, the invasion of Europe. The 21st Army Group operated in Northern France, Luxembourg, Belgium, the Netherlands and Germany from June 1944 till the end of the war in Europe in 1945, after which it was redesignated the British Army of the Rhine (BAOR).

Normandy[link]

Commanded by General (later Field Marshal) Sir Bernard Montgomery, 21st Army Group initially controlled all ground forces in Operation Overlord. When sufficient American forces had landed, their own 12th Army Group was activated, under General Omar Bradley and the 21st Army Group was left with the British 2nd Army and the First Canadian Army under its control.

Normandy was a battle of attrition for the British and Canadian armies, drawing in the available German reinforcements around Caen at the eastern end of the lodgement. The German Wehrmacht lacked the ability to prevent the American breakout at the western end of the Normandy beachhead in early August 1944. The Germans were nearly enveloped at the Falaise and routed.

Advance into the Netherlands[link]

After the successful landings in the south of France by the U.S. 6th Army Group, the 21st Army Group formed the left flank of the three Allied army groups arrayed against German forces in the West. It was therefore responsible for securing the ports upon which Allied supply depended, and also with overrunning German V-1 and V-2 launching sites along the coasts of western France and Belgium.

By 29 August, the Germans had largely withdrawn across the Seine River without their heavy equipment. The campaign through Northern France and Belgium was largely a pursuit, with the ports - formally designated "Fortress Towns" by the Germans - offering only limited opposition to the First Canadian Army. The advance was so rapid, 250 miles in four days, that Antwerp, Belgium was captured on 4 September 1944, undefended, and with its port facilities intact.

On 1 September 1944, the 21st Army Group was relieved of operational control of the American armies, and those armies formed the 12th Army Group.

By mid-September, elements of 21st Army Group had reached the Dutch border, but were halted due to lack of supplies, and by flooding caused by the widespread German demolition of Dutch dikes. German control of some of the channel ports, and previous Allied bombing of the French and Belgian railways, resulted in a long supply line from Normandy served mainly by trucks.

Operation Market Garden[link]

After the break-out from Normandy, there were high hopes that the war could be ended in 1944. In order to do so, the last great natural defensive barrier of Germany in the west, the Rhine River had to be crossed. Operation Market Garden was orchestrated to attempt just this. It was staged in the Netherlands with two American and one British airborne divisions and a Polish parachute brigade being dropped to capture bridges over the lower Rhine before they were blown by the Germans. The airborne formations were then to be relieved by armored forces advancing rapidly northwards through Eindhoven and Nijmegen to Arnhem, opening the north German plains, and the industrial Ruhr Valley, to the Allies.

However, the British armored forces had only one main highway to operate on, and crucial information about the German forces in the operational area was either missing or ignored. The scratch forces remaining after the retreat from France were much stronger than expected, thus giving the armored units of the XXX Corps a much tougher fight than had been anticipated, slowing the advance. The American divisions and the Polish parachute brigade that had fought south of the Rhine were relieved but the British 1st Airborne Division in Arnhem was practically destroyed.

Battle of the Scheldt[link]

Since the approaches to the port of Antwerp had not been cleared when the city was captured it had allowed the German army time to reorganise and dig in along the approaches making the port completely unusable. Thus an operation was needed to clear the approaches and thereby ease the supply problem. The island of Walcheren was strongly held by German forces and commanded the estuary of the Scheldt which flows through Antwerp. Operations by II Canadian Corps cleared the approaches to Antwerp both north and south of the water during the Battle of the Scheldt. Walcheren itelf was captured in late 1944 by the last major amphibious assault in Europe in the Second World War. A combination of Canadian forces and Royal Marines undertook the operation.

Battle of the Bulge[link]

After the capture of Walcheren came the last great German offensive of the war. In a repeat of their 1940 attack, German formations smashed through weak Allied lines in the Ardennes in Belgium.

The Battle of the Bulge presented a command problem to General Eisenhower. It had sliced through US lines, leaving some American formations north and south of the new German salient. However, the headquarters of U.S. 12th Army Group lay to the south, and so Eisenhower decided to place American forces north of the "Bulge" salient under 21st Army Group. They, with the American 3rd Army under General George S. Patton, reduced the salient.

After the battle, control of the U.S. 1st Army which had been placed under Field Marshal Montgomery's temporary command was returned to Bradley's 12th Army Group. The U.S. 9th Army remained under Montgomery longer, before being returned to American command in Germany.

Battle for the Roer Triangle[link]

Prior to the Rhineland Campaign the enemy had to be cleared from the Roer Triangle during Operation Blackcock. This large methodical mopping up operation took place between 14 and 27 January 1945. It was not planned to make any deep thrust into the enemy defences or capture large numbers of prisoners. It proceeded from stage to stage almost entirely as planned and was completed with minimal casualties.

Rhineland Campaign[link]

Allied forces closed up to the Rhine by March 1945. Twenty-First Army Group at this time comprised the British Second Army under General Miles C Dempsey, the First Canadian Army under General Harry Crerar and the US Ninth Army, under General William Simpson.

The First Canadian Army had executed Operation Veritable in difficult conditions from Nijmegen eastwards through the Reichswald Forest then southwards. This was to have been the northern part of a pincer movement with the US Ninth Army moving northwards towards Düsseldorf and Krefeld (Operation Grenade), to clear the west bank of the Rhine north of Cologne. However the Americans were delayed by two weeks when the Germans destroyed the Roer dams and flooded the American route of advance. As a result the Canadians engaged and mauled the German reserves intended to defend the Cologne Plain.

In Operation Plunder, starting on 13 March 1945, the British 2nd Army and the US 9th Army crossed the Rhine at various places north of the Ruhr and German resistance in the west quickly crumbled. The First Canadian Army wheeled left and liberated northern Holland, the British 2nd Army occupied much of north-west Germany and liberated Denmark and the US 9th Army formed the northern arm of the envelopment of German forces in the Ruhr Pocket and on 4 April reverted to Bradley's 12th Army Group.

British Army Of the Rhine[link]

After the German surrender, 21st Army Group was converted into the headquarters for the British zone of occupation in Germany. It was renamed the British Army of the Rhine (BAOR) on 25 August 1945 and eventually formed the nucleus of the British forces stationed in Germany throughout the Cold War.

Order of battle[link]

The main constituent formations of 21st Army Group were the First Canadian Army and the British 2nd Army. In practice, neither of the two armies were homogeneously British or Canadian. Also included were Polish units, from Normandy onwards and small Dutch, Belgian, and Czech units; American Army forces were attached from time to time. Lines of communications units were predominantly British.

Attached U.S. units[link]

American army units were placed under British command at various times. For political and personal rivalry reasons, these were never more than temporary. These arrangements occurred when

1. the First Allied Airborne Army, including two U.S. airborne divisions (the 101st and 82nd), was deployed during Operation Market Garden and subsequent holding actions;
2. as reinforcement to the First Canadian Army during the Battle of the Scheldt (104th Infantry Division)
3. as a result of the disruption to the command chains during the Battle of the Bulge (the U.S. First and Ninth Armies);
4. as reinforcement for the drive to the Rhine (Operations Veritable and Grenade) (U.S. Ninth Army) and the subsequent Rhine crossings (Operations Plunder and Varsity) (U.S. Ninth Army and U.S. XVIII Airborne Corps;
5. to allow an efficient command structure during the Geilenkirchen salient (84th Infantry Division).

Commanders[link]

• June 1943 – December 1943 General Bernard Paget^[1]
• January 1944 – August 1945 General Bernard Montgomery^[2]

Notes[link]

References[link]

• Defeat in the West; Milton Shulman, first published 1947
• The Struggle for Europe; Chester Wilmot
• canadiansoldiers.com page, including uniform insignia images

This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. (June 2010)

Standard NATO symbol for an Army Group / Front

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 a General Army (Sō-gun (総軍^?)).

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[link]

China[link]

Main article: Army Groups of the National Revolutionary Army

Main article: Group Army

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[link]

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[link]

During World War II there were six General Armies:

• Kantōgun (often known as the "Kwantung Army") originated as the division-level garrison of a Japanese colony in northeast China, in 1908; it remained in northern China until the end of World War II. The strength of the Kantōgun peaked at 700,000 personnel in 1941. It faced and was destroyed by Soviet forces in 1945.

• Shina Hakengun, the "China Expeditionary Army", was formed in Nanjing, in September 1939, to control operations in central China. At the end of World War II, it consisted of 620,000 personnel in 25 infantry and one armored divisions.

• Nanpo Gun was the "Southern Army", also known as the "Southern Expeditionary Army". By November 1941, war with the western Allies appeared likely and Nanpo Gun was formed in Saigon, French Indochina, to control IJA operations in southern China, South Asia, South East Asia, and the South Pacific.

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:

• Dai-Ichi So-Gun ("1st General Army", headquartered in Tokyo)
• Dai-Ni So-Gun ("2nd General Army", headquartered in Hiroshima)
• Koku So-Gun ("Air General Army", headquartered in Tokyo)

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[link]

The Soviet Army was organized into Fronts (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[link]

In April 1944, the previously informal British-United States collaboration in the European Theater was strengthened by the establishment in London of a formal planning headquarters called Chief of Staff Supreme Allied Command, or COSSAC, and 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. General 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.

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.

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'[link]

Northern Army Group

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.^[1]

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.^[2] 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.

References[link]