Army Group A (Heeresgruppe A) was the name of several German Army Groups during World War II.
Western Front 1940 Edit
During the German invasion of the Low Countries and France Army Group A was under the command of Generaloberst Gerd von Rundstedt and was responsible for the break-out through the Ardennes. It was composed of 45½ divisions, including the 7 Panzer divisions of Panzer Group Kleist.
Eastern Front 1942-45 Edit
In 1942, Army Group South was in southern Russia on the Eastern Front. For Case Blue (Fall Blau), the summer offensive of the German Armed Forces (Wehrmacht), Army Group South was split into Army Group A and Army Group B. Army Group A was ordered south to capture the oil fields in the Caucasus.
On January 16, 1945 Colonel Bogislaw von Bonin, the Chief of the Operational Branch of the Army General Staff (Generalstab des Heeres) gave Heeresgruppe A permission to retreat during the Soviet Vistula-Oder Offensive, rejecting a direct order from Adolf Hitler for them to hold fast. Although Heeresgruppe A escaped encirclement and regrouped, von Bonin was arrested by the Gestapo on January 19, 1945, and imprisoned first at Flossenbürg concentration camp and then Dachau concentration camp. He was eventually liberated along with other prisoners in South Tyrol by the US Army in May 1945.
On 25 January 1945 Hitler renamed three army groups. Army Group North became Army Group Courland; Army Group Centre became Army Group North and Army Group A became Army Group Centre.
Wikipedia page, 6th of November 2017.