21st Army Group

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21st Army Group
Active July, 1943 to August, 1945
Country Flag of the United Kingdom United Kingdom
Canada
Flag of Poland Poland
Part of Supreme Headquarters Allied Expeditionary Force (SHAEF)
Commanders
Notable
commanders		 Bernard Montgomery

The Twenty-first Army Group was a formation comprising British and Canadian forces stationed in the United Kingdom. who were assigned for the invasion of Europe. The formation was established in London in July of 1943. The Group was an important Allied force in the European Theatre of World War II. The Twenty-First Army Group operated in Northern France, Luxembourg, Belgium, Holland and Germany.

Contents

[edit] Normandy

Commanded by General (later Field Marshal) Sir Bernard Montgomery, Twenty-First 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 formation was left with British Second Army and First Canadian Army under its control.

Normandy was a battle of attrition for the British and Canadian armies, sucking in the available German reinforcements around Caen at the eastern end of the lodgement. In the end the Germans lacked the reserves and air protection to prevent the US breakout at the western end in early August, 1944 and they were routed.

[edit] Advance into Holland

After the successful landings in the south of France by the U.S. 6th Army Group, Twenty-First 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.

By 29 August, the Germans had largely crossed the Seine, but without their heavy equipment. The campaign through Northern France and Belgium was largely a pursuit, with the ports - formally designated "Fortress Towns" - offering only limited opposition to the Canadian 1st Army. Their facilities were destroyed though. The advance was so rapid, 250 miles in 4 days, that Antwerp was captured on 4th September undefended and with its port facilities intact.

On September 1, the Twenty-first Army Group was relieved of operational control of the United States Armies and these Armies became the chief components of the Twelfth Army Group.

By mid September, elements of Twenty-First Army Group had reached Holland and halted. Supplies were short. The long haul from Normandy had to be by truck. Ports and railways were unusable. Eisenhower had to choose which line of advance to supply - the Allies could not do it all.

[edit] Operation Market Garden

The Twenty-First Army Group then took part in one of the most famous operations in WWII; Operation Market Garden.

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 River Rhine had to be crossed. Operation Market Garden was the first attempt to do this. It was staged in the Netherlands with American and British parachute divisions and a Polish parachute brigade being dropped to capture bridges over the lower Rhine before they were blown by the Germans. The parachute formations would then be relieved by armoured forces advancing rapidly northwards through Eindhoven and Nijmegen to Arnhem. The north German plain would then be open to the Allies.

However, the armoured formations would have only one road to use - referred to as a "battlefront two tanks wide".[citation needed] Crucial information about the German formations in the area was either missing or ignored. The scratch forces remaining after the retreat from France were much stronger than expected, thus giving the armoured units of 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.

[edit] Walcheren

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 Meuse which flows through Antwerp. It was captured in late 1944 by the last major amphibious assault in Europe in WWII. A combination of Canadian forces and Royal Marines undertook the operation.

[edit] Battle of the Bulge

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. However, unlike 1940, the Allies were able to blunt the attack and then destroy the forces that had mounted it.

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, so US forces north of the salient were placed under Twenty-First Army Group. They with U.S. Third Army under General George Patton, reduced the salient.

After the battle, control of U.S. First Army which had been placed under Montgomery's temporary command was returned to Bradley's 12th Army Group. U.S. Ninth Army remained under Montgomery for the final attack into Germany.

[edit] Battle for the Roer Triangle

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.

[edit] Rhineland Campaign

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 Canadian 1st Army under General Harry Crerar and the US Ninth Army, under General William Simpson.

The Canadian 1st 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. 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 Second Army and the US Ninth Army crossed the Rhine at various places north of the Ruhr and German resistance in the west quickly crumbled. The Canadian First Army wheeled left and liberated northern Holland, the British Second Army occupied much of north-west Germany and liberated Denmark and the US Ninth 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.

[edit] British Army of the Rhine

After the German surrender, Twenty-First 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.

[edit] Order of battle

The main constituent formations of Twenty-First Army Group were the 1st Canadian Army and the 2nd British 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; U.S. units were attached from time to time. British units were included in the Canadian Army.

[edit] Attached U.S. units

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 a result of the disruption to the command chains during the Battle of the Bulge (the U.S. First and Ninth Armies);
  3. 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;
  4. to allow an efficient command structure during the Geilenkirchen salient (84th Infantry Division).

[edit] Notes

[edit] References