Antietam , also knows in the South as the Battle of Sharpsburg , was the bloodiest one - day battle ever fought in American history .
The Battle of South Mountain occurred two days before the larger battle of Antietam which took place on September 17 , 1862 .
Antietam , also knows in the South as the Battle of Sharpsburg , was the bloodiest one - day battle ever fought in American history .
The Battle of South Mountain occurred two days before the larger battle of Antietam which took place on September 17 , 1862 .