Aisne.
3. From June, 1915, until June, 1916, the 15th Division occupied various sectors of the Aisne: Vailly-Pommiers (end of July), Nouvron (September), Ste. Marguerite-Bucy le Long (October).
1916.
Somme.
1. July, 1916, the 15th Division was transferred to the Somme. It took part in the battle and participated in the attack at Biaches, where it suffered heavy losses.
2. At the end of August it again took over its sector, St. Marguerite-Bucy le Long. Its composition was modified by the temporary loss of the 160th Infantry Regiment, sent to the combined division of Dumrath (August), by the definite transfer of the 65th Infantry Regiment and the 161st Infantry Regiment to the 185th Division, and of the 25th Infantry Regiment to the 208th Division.
3. At the beginning of October it had received in exchange for the regiments transferred the 186th Infantry Regiment (temporarily) and the 389th Infantry Regiment, a new formation (men taken from various Rhine regiments), and received the 160th Infantry Regiment again (the Dumrath Division having been dissolved). It reappeared on the Somme front (Sailly-Saillisel), where it again suffered heavy losses.
Aisne.
4. At the end of October it returned to the Aisne and occupied the sectors of Nuvron-Moulin sous Touvent. It was reorganized finally in November and received its definitive composition.