21st Army Group

21st Army Group
Skjoldbro · Public domain · source
Dates	1943–1945
Country	United Kingdom
Branch	British Army
Type	Army group
Command structure	Supreme Headquarters Allied Expeditionary Force
Battles	Operation Overlord, Operation Market Garden, Battle of the Bulge, Operation Veritable, Western Allied invasion of Germany
Commander1 label	Notable commanders

21st Army Group was the principal Allied ground force command in Northwestern Europe during the latter stages of the Second World War. Formed from the British Expeditionary Force, it commanded all British and Canadian ground forces, later incorporating American and other Allied units. Under the leadership of Field Marshal Bernard Montgomery, it played a central role in the Normandy landings, the liberation of France, and the final advance into Nazi Germany.

Formation and command

The formation was officially activated in July 1943 under the command of General Bernard Montgomery, who had previously led the Eighth Army to victory at the Second Battle of El Alamein. Its headquarters was established at St Paul's School in London, where Montgomery had also been a student. The command structure was part of the broader Supreme Headquarters Allied Expeditionary Force under Supreme Allied Commander Dwight D. Eisenhower. Key subordinate commanders included Miles Dempsey of the British Second Army and Harry Crerar of the First Canadian Army, with Omar Bradley's 12th Army Group operating on its right flank during the campaign in Europe.

Operational history

Following its activation, the group began intensive planning for Operation Overlord, the Allied invasion of Normandy. On D-Day, June 6, 1944, it landed on Gold Beach, Juno Beach, and Sword Beach, securing a vital foothold in France. After the difficult Battle of Normandy and the closure of the Falaise pocket, it advanced rapidly across Northern France and into Belgium, liberating Brussels and Antwerp. Its operational tempo was marked by the ambitious but contested Operation Market Garden in the Netherlands, the defensive role during the Battle of the Bulge in the Ardennes, and the grueling Operation Veritable in the Reichswald. The final phase of its war saw the crossing of the Rhine during Operation Plunder and the subsequent advance across the North German Plain.

Order of battle

The primary components for much of the campaign were the British Second Army and the First Canadian Army. The Second Army, commanded by Miles Dempsey, included renowned formations such as I Corps, VIII Corps, XII Corps, and XXX Corps, featuring divisions like the Guards Armoured Division and the 7th Armoured Division. The First Canadian Army, under Harry Crerar, was a multinational force containing the II Canadian Corps and, at various times, the Polish 1st Armoured Division, the 1st Belgian Infantry Brigade, and the Royal Netherlands Brigade. During certain operations, it also exercised command over the US Ninth Army led by William Hood Simpson.

Campaigns and battles

Its major campaigns began with the Normandy landings and the subsequent Battle for Caen. This was followed by operations to break out of the Normandy bridgehead, including Operation Goodwood and Operation Totalize. The drive across France included the liberation of Paris and the fierce fighting to secure the Scheldt estuary. The failed thrust towards Arnhem during Operation Market Garden in September 1944 was a significant setback. After regrouping, it faced the German Ardennes Offensive in December 1944, contributing forces to the northern shoulder of the Battle of the Bulge. The final offensives into Germany in 1945 included the brutal Battle of the Reichswald and the crossing of the Rhine River at Wesel, culminating in the capture of Bremen, Hamburg, and a link-up with the Soviet Red Army along the Elbe.

Disbandment and legacy

Following the German Instrument of Surrender in May 1945, it assumed control of the British Occupation Zone in northwestern Germany. Its headquarters effectively became the administration for this zone, dealing with Disarmed Enemy Forces, Displaced persons, and initial Denazification efforts. The formation was officially disbanded in August 1945, with its responsibilities and remaining units absorbed into the peacetime British Army of the Rhine. The group's legacy is defined by its pivotal role in the Western Front, its complex command relationships within the Allied coalition, and its commander's enduring, if controversial, place in military history.

Category:Army groups of the British Army in World War II Category:Military units and formations established in 1943 Category:Military units and formations disestablished in 1945