This mountain range extends from the Potomac River and runs the depth of eastern Maryland into Pennsylvania. Elements of both armies moved from the Frederick area to the Antietam battlefield over the South Mountain. As Lee began concentrating around Sharpsburg, he ordered the gaps defended. Federals, trying to relieve the siege at Harpers Ferry, attacked Crampton’s Gap Sept. 14, 1862, while other Union forces assaulted Fox's Gap and Turner's Gap, following Lee’s army. The thin but stubborn Confederate defense purchased much-needed time for Lee – both to capture Harpers Ferry and construct a defense near Sharpsburg.
All three gaps offer interpretation of the battle.
The more foreboding and cautionary tale which increasing numbers of Western historians have offered in place of Turner's account has provoked sharp controversy. "New" Western historians -- many of whom actually echo and draw upon fairly old scholarly works -- often argue that their accounts offer a more inclusive and honest reckoning of the Western past. Western historians who still adhere roughly to Turner's approach accuse their opponents of mistaking a simple-minded political correctness for good scholarship in their quest to recount only the doom and gloom of the Western past. Often the rhetoric reaches an acrimonious crescendo. But in a sense, the very acrimony of these debates takes us full circle back to Turner and his legacy, for debates about the significance of Western history are hardly ever confined to the past. In our understanding of what we are as a nation, if on no other level, the Western past continues to define us today.