South Mountain, MD

Date(s): September 14, 1862

Campaign(s): Maryland Campaign [September 1862]

Battles in Campaign:



  • Union: Maj. Gen. George B. McClellan

  • Confederate: Gen. Robert E. Lee

Principal Forces: Corps

  • Union:

  • Confederate:


  • After invading Maryland in September 1862, Gen. Robert E. Lee divided his army to march on and invest Harpers Ferry.

  • The Army of the Potomac under Maj. Gen. George B. McClellan pursued the Confederates to Frederick, Maryland, then advanced on South Mountain.

  • On September 14th, pitched battles were fought for possession of the South Mountain passes: Crampton’s, Turner’s, and Fox’s Gaps.

  • By dusk the Confederate defenders were driven back, suffering severe casualties, and McClellan was in position to destroy Lee’s army before it could re-concentrate.

  • McClellan’s limited activity on September 15th after his victory at South Mountain, however, condemned the garrison at Harpers Ferry to capture and gave Lee time to unite his scattered divisions at Sharpsburg.

Slide Presentation: None

Classification2: B

Casualties3: 4,500

  • Union:

  • Confederate:

Results: Union Victory

Battlefield Websites: 

Recommended Resources:

1 National Park Service summary.

2 Classification:

  • A - having a decisive influence on a campaign and a direct impact on the course of the war

  • B - having a direct and decisive influence on their campaign

  • C - having observable influence on the outcome of a campaign

  • D - having a limited influence on the outcome of their campaign or operation but achieving or affecting important local objectives

3 Casualties are someone killed, injured, wounded, captured or missing.

Revised 01/25/2011