South Mountain (American Civil War).
Fought September 14, 1862, between the Federals, under General M’Clellan, and the Confederates, under General Lee. Lee's object was to hold M’Clellan in check while Jackson captured Harper's Ferry, and to this end he posted General D. Hill with 15,000 on South Mountain. Here Hill was attacked, and driven to the upper slopes, but being reinforced by a portion of Longstreet's command, he maintained his position there, withdrawing on the morning of the 15th. Each side lost about 2,500 men, but Lee had gained his object, as the delay to M’Clellan ensured the capture of Harper's Ferry.