The Ninth Army, first named "détachement d'armée Foch", was formed for the first time on 29 August 1914, to fill the gap between the Fourth and Fifth Army.
The Ninth Army was recreated on 6 July 1918 under command of Antoine de Mitry to fight in the Second Battle of the Marne.
In 1940, it was initially the only part of the French army that faced the Germans directly as they came unexpectedly through the Ardennes during the early stages of the Fall of France.
It included the 41st Army Corps, of two fortress divisions.
This article about a specific French military unit is a stub.