It was fought between French, British and Dominion forces and the German Empire in the Somme River valley and vicinity in northern France.

Battle nomenclature and participating units information taken from source British Army Council Command Notice 1138 unless stated.

German order of battle derived from Hart, Appendix C unless stated.

Commander: General der Infanterie Fritz von Below On 19 July, split into the 1st Army (opposite the British) and the 2nd Army, Commander: General der Artillerie Max von Gallwitz (opposite the French) with authority over the 1st Army as Armeegruppe Gallwitz-Somme, this was not an army group, the term for which was Heeresgruppe Chief of the German General Staff: General der Infanterie Erich Falkenhayn (until 28 August 1916), Generalfeldmarschall Paul von Hindenburg.

German divisions were being converted from square to triangular, hence some had four infantry regiments, others had three.