of South Mountain
The Battle of South Mountain (known in several early Southern accounts as
the Battle of Boonsboro Gap) was fought 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. Maj. Gen. George B. McClellan, commanding the
Union Army of the Potomac, needed to pass through these gaps in his
pursuit of Confederate General Robert E. Lee's Army of Northern Virginia.
Despite being significantly outnumbered, Lee's army delayed McClellan's
advance for a day before withdrawing.
South Mountain is the name given to the continuation of the Blue Ridge
Mountains after they enter Maryland. It is a natural obstacle that
separates the Shenandoah Valley and Cumberland Valley from the eastern
part of Maryland.
After Lee invaded Maryland, a copy of an order, known as order 191,
detailing troop movements that he wrote fell into the hands of McClellan.
From this, McClellan learned that Lee had split his forces and the Union
general hoped to attack and defeat some of these isolated forces before
they could concentrate against him. To reach Lee, McClellan had to move
across South Mountain. Lee learned of McClellan's intelligence coup and
quickly sent forces to reinforce the passes to block his advance.
McClellan temporarily organized his army into three wings for the attacks
on the passes. Maj. Gen. Ambrose Burnside, the Right Wing, commanded the I
Corps (Maj. Gen. Joseph Hooker) and IX Corps (Maj. Gen. Jesse L. Reno).
The Right Wing was sent to Turner's Gap and Fox's Gap in the north. The
Left Wing, commanded by Maj. Gen. William B. Franklin, consisting of his
own VI Corps and Maj. Gen. Darius N. Couch's division of the IV Corps, was
sent to Crampton's Gap in the south. The Center Wing (II Corps and XII
Corps), under Maj. Gen. Edwin V. Sumner, was in reserve.
At the southernmost point of the battle, near Burkittsville, Confederate
cavalry and a small portion of Maj. Gen. Lafayette McLaws's division
defended Brownsville Pass and Crampton's Gap. McLaws was unaware of the
approach of 12,000 Federals and had only 500 men under Col. William A.
Parham thinly deployed behind a three quarter-mile-long stone wall at the
eastern base of Crampton's Gap. Franklin spent three hours deploying his
forces. A Confederate later wrote of a "lion making exceedingly careful
preparations to spring on a plucky little mouse." Franklin deployed the
division of Maj. Gen. Henry W. Slocum on the right and Maj. Gen. William
F. "Baldy" Smith on the left. They seized the gap and captured 400
prisoners, mostly men who were arriving as late reinforcements from Brig.
Gen. Howell Cobb's brigade.
Confederate Maj. Gen. D.H. Hill, deploying 5,000 men over more than 2
miles, defended both Turner's Gap and Fox's Gap. Burnside sent Hooker's I
Corps to the right and Turner's Gap. The Union Iron Brigade attacked
Colonel Alfred H. Colquitt's small brigade along the National Road,
driving it back up the mountain, but it refused to yield the pass. Hooker
positioned three divisions opposite two peaks located one mile north of
the gap. The Alabama Brigade of Brig. Gen. Robert E. Rodes was forced to
withdraw because of his isolated position, despite the arrival of
reinforcements from Brig. Gen. David R. Jones's division and Brig. Gen.
Nathan G. Evans's brigade. Darkness and the difficult terrain prevented
the complete collapse of Lee's line. At nightfall, the Confederates still
held the gap.
Just to the south, other elements of Hill's division defended Fox's Gap
against Reno's IX Corps. A 9 a.m. attack by Union Brig. Gen. Jacob D.
Cox's Kanawha Division secured much of the land south of the gap. In the
movement, Lt. Col. Rutherford B. Hayes of the 23rd Ohio led a flank attack
and was seriously wounded. Cox pushed through the North Carolinians
positioned behind a stone wall at the gap's crest, but he failed to
capitalize on his gains as his men were exhausted, allowing Confederate
reinforcements to deploy in the gap around the Daniel Wise farm. Reno sent
forward the rest of his corps, but due to the timely arrival of Southern
reinforcements under Confederate Brig. Gen. John Bell Hood, they failed to
dislodge the defenders. Union Maj. Gen. Jesse Reno and Confederate Brig.
Gen. Samuel Garland, Jr., were killed at Fox's Gap. Union soldiers dumped
60 Confederate bodies down Farmer Wise's well, paying him $60 in
By dusk, with Crampton's Gap lost and his position at Fox's and Turner's
Gaps precarious, Lee ordered his outnumbered forces to withdraw from South
Mountain. McClellan was now in position to destroy Lee's army before it
could concentrate. Union casualties of 28,000 engaged were 2,325 (443
killed, 1,807 wounded, and 75 missing); Confederates lost 2,685 (325
killed, 1560 wounded, and 800 missing) of 18,000. McClellan's limited
activity on September 15 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.