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BATTLE // September 14, 1862

Battle of South Mountain

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Overview

The Battle of South Mountain, known in several early Southern accounts as the Battle of Boonsboro Gap, was fought on September 14, 1862, as part of the Maryland campaign of the American Civil War. Three pitched battles were fought for possession of three South Mountain passes: Crampton's, Turner's, and Fox's Gaps.

Overview adapted from Wikipedia, licensed under CC BY-SA 4.0.

Significance

The Battle of South Mountain was a component engagement of the Maryland Campaign, in which Union forces under McClellan pressed against Confederate positions holding three passes through South Mountain: Crampton's, Turner's, and Fox's Gaps. The engagement involved three separate pitched battles for control of these passes, with Confederate forces under Lee and D. H. Hill contesting a Union force that outnumbered them by roughly 10,000 men. Confederate casualties slightly exceeded Union losses despite the defenders' positional advantage. The battle is known in some early Southern accounts as the Battle of Boonsboro Gap, reflecting the geographic stakes of the contest over mountain passage routes during Lee's incursion into Maryland.

Tactics

The battle was fought across three South Mountain passes — Crampton's Gap, Turner's Gap, and Fox's Gap — with three separate pitched engagements for possession of each. Beyond the multi-gap structure of the fighting, the supplied overview does not detail the specific maneuvers, formations, or dispositions employed by either side.

Forces & casualties

Troop strength

  • United States28,000
    medium
  • Confederate States18,000
    medium

United States fielded a 1.6 : 1 numerical advantage

Casualties

  • United States2,325
    medium8% loss rate
  • Confederate States2,685
    medium15% loss rate

Commanders (5)

Confederate States

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Related

6 sibling battles · 2 factions

Last verified June 2026
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