1. The 18th Reserve Division formed the 9th Reserve Corps, with the 17th Reserve Division.
Belgium.
2. From the outbreak of the war until August 22, 1914, the 18th Reserve Division was guarding the coast of Schleswig-Holstein. Entraining about this time, it went into Belgium, where it advanced rapidly. After taking and sacking Louvain (Aug. 25) it occupied Hamme (Sept. 1), Termonde (Sept. 4).
Oise.
3. On the 9th it was hastily transferred by way of Tournai and Valenciennes to the Oise area. Entraining on the 13th at Chauny, it reenforced the front south of Noyon and went into action between Carlepont and Lassigny (Sept. 15–21).
4. At the beginning of October the 18th Reserve Division was taken to the valley of the Avre. It fought in the vicinity of Roye (Laucourt, Oct. 2–3). At the beginning of November the division front extended between the Avre and Beuvraignes.
Lassigny.
5. On November 15 it bore to the south and held the region of the Loges-Lassigny wood.
1915.
In March, 1915, it gave the 90th Reserve Infantry Regiment to the 54th Division, a new formation.