The Lochnagar mine was a mine dug by the 179th Tunnelling Company Royal Engineers, under a German field fortification known as Schwabenhöhe, in the front line south of the village of La Boisselle in the Somme département of France. The mine was sprung at 7:28 a.m. on 1 July 1916, the first day of the Battle of the Somme, as the infantry of the British 34th Division, which was composed of Pals battalion from the north of England, attacked the positions of Reserve Infantry Regiment 110 of the German 28th Reserve Division, mainly recruited from Baden, on either side of La Boisselle. The crater was captured and held by British troops but the attack on either flank was defeated by German small-arms and artillery fire, except on the extreme right flank and just south of La Boisselle, north of the new crater. The 34th Division incurred the largest number of casualties of the British divisions which attacked on 1 July.