1862
Battle of South Mountain
The setting
Frederick and Washington Counties, Maryland (Crampton's, Turner's, and Fox's Gaps), United States
Mountain ridge passes and gaps of South Mountain
Reveal the outcome
Recorded sideConfederate States
Recorded resultdefeat (delaying action)
Union victory; Confederates forced from the mountain gaps but bought time to concentrate at Sharpsburg
How the atlas explains it
Acting on Lee's captured Special Order 191, McClellan pushed through the South Mountain gaps; superior Union numbers eventually forced the outnumbered Confederate defenders off the heights, though the stubborn defense delayed the Union advance long enough for Lee to regroup at Antietam.
What followed
First major clash of the Maryland Campaign, three days before Antietam. Union Major General Jesse L. Reno was killed here; the city of Reno, Nevada, is named in his honor. The battle forced Lee to abandon his campaign plan and consolidate at Sharpsburg.