Argonne-Champagne.
3. At the battle of the Marne it went into action on the Saulx in the vicinity of Mognéville (Sept. 7–10, south of Revigny). It effected its retreat by way of the Givry en Argonne, Ste. Menehould, Vienne la Ville, and stopped on the heights to the south of Cernay en Dormois on September 14.
4. The 21st Reserve Division established its positions in the sector of Ville sur Tourbe and remained there until June, 1916.
1915.
Champagne.
1. From January to December, 1915, the division was in the sector of Ville sur Tourbe north of Massiges à L’Aisne.
2. In September the division took part in the Champagne battle.
1916.
1. The 21st Reserve Division continued to occupy the Massiges sector from January to June, 1916.