Battles of the Somme, two engagements fought during World War I near the Somme River, N France. The first battle (July–Nov., 1916) was an Allied offensive. The British, commanded by Field Marshal Sir Douglas Haig, had the largest Allied role; a smaller French contingent also fought. On the first day of the attack against the heavily fortified 21-mi (34-km) German line, the British suffered the largest one-day loss in their history—some 19,000 dead and 40,000 injured. British tanks joined the fray in September, but after nearly five months the Allies had gained little territory despite terrible slaughter. Some 131,000 Britons died and more than 288,000 were wounded. The French suffered more than 204,000 casualties; the Germans between 450,000 and 600,000. The battle, which did serve to ease German pressure on Verdun (see Verdun, battle of), nonetheless became a lasting symbol of war's fruitless carnage.

The second battle (Mar.–Apr., 1918), or the Somme Offensive, was a German attack led by Gen. Erich Ludendorff against the weakened 60-mi (92-km) British line N of the Somme, which the Germans hoped to breach before American reinforcements arrived. The British lines were soon overrun, and the British forced back some 40 mi (64 km). The French, under Gen. Ferdinand Foch, reinforced the British, and the German advance was halted. The German victory had little effect on the larger war, however, as it further depleted Germany's forces. The British suffered some 163,000 casualties, and the French 77,000; the Germans nearly as many.

See study by M. Middlebrook (2007) on both battles. The first battle is the subject of studies by J. Buchan (1917), A. R. Dugmore (1918), B. Gardner (1961), A. Farrar-Hockley (1964), J. Harris (1966), M. Middlebrook (1971, repr. 2007), C. Martin (1973), L. Macdonald (1983), T. Norman (1984, repr. 2003), P. Liddle (1992), C. McCarthy (1993), M. Chappell (1995), G. Sheffield (2003), P. Hart (2005, repr. 2009), R. Prior and T. Wilson (2005), C. Duffy (2006), D. Youel (2006), M. Gilbert (2006), G. Gliddon (1989 and 2006), and A. Robertshaw (2006). Studies devoted to the second battle include those by R. Cowley (1964), J. Giles (1977), M. Marix Evans (1996), M. Stedman (2001), and S. Ross (2004).