The battle began on 15 July 1918 when 23 German divisions of the First and Third armies—led by Bruno von Mudra and Karl von Einem—assaulted the French Fourth Army under Henri Gouraud east of Reims (the Fourth Battle of Champagne (French: 4e Bataille de Champagne)). The U.S. 42nd Division was attached to the French Fourth Army and commanded by Gouraud at the time. Meanwhile, 17 divisions of the German Seventh Army, under Max von Boehn, aided by the Ninth Army under Johannes von Eben, attacked the French Sixth Army led by Jean Degoutte to the west of Reims (the Battle of the Mountain of Reims (French: Bataille de la Montagne de Reims)). Ludendorff hoped to split the French in two.

"German soldiers advancing past a captured French position, between Loivre and Brimont, Marne department, 1918"[attribution needed]

The German attack on the east of Reims was stopped on the first day, but west of Reims the offensive fared better. The defenders of the south bank of the Marne could not escape the three hour bombardment. Under cover of gunfire, stormtroopers swarmed across the river in every sort of transport—30-man canvas boats or rafts. They began to erect skeleton bridges at 12 points under fire from those Allied survivors who had not been suppressed by gas or artillery fire. Some Allied units, particularly COL Ulysses G. McAlexander's 38th Infantry Regiment of the 3rd U.S. Infantry Division, "Rock of the Marne," held fast or even counterattacked, but by the evening, the Germans had captured a bridgehead either side of Dormans 4 mi (6.4 km) deep and 9 mi (14 km) wide, despite the intervention of 225 French bombers, which dropped 44 short tons (40 t) of bombs on the makeshift bridges.

The British XXII Corps and 85,000 American troops joined the French for the battle, and stalled the advance on 17 July 1918.

Alfred C Schmitt