Hartmannswillerkopf, also known as the Vieil Armand or Hartmannsweilerkopf is a pyramidal rocky spur in the Vosges mountains of Alsace. The peak stands at 956 metres (3,136 ft) overlooking the Rhine valley.
The mountain peak was a strategic area bitterly fought for by both sides. The most severe fighting for the peak took place on 19–20 January, 26 March, 25–26 April and 21–22 December 1915. Amongst the casualties was General Marcel Serret, commander of the 66th Infantry Division. After nearly a year of attacks and counter-attacks, both sides began to attack further north on the Western Front. Only enough men to hold the lines were left at Hartmannswillerkopf and the lines remained relatively stable for the remainder of the war and generally only artillery exchanges took place. About 30,000 men died near Hartmannswillerkopf, the majority of deaths suffered by the French.