The single bloodiest day in the 
Civil War began at dawn, 
September 17th, 1862.  The Army 
of the Potomac and the Army of 
Northern Virginia would engage 
in a fierce, epic battle for 
more than 12 hours.

Determined to salvage something 
from his so far unremarkable 
invasion of Maryland, Lee 
regrouped his army at Sharpsburg
between September 15th and 16th.
Even though he was outnumbered 
2 to 1 and his ranks were 
severely depleted from 
straggling, Lee sent two corps 
across Antietam Creek to engage 
the Union's General McClellan.

McClellan, taking the 
initiative, sent Hooker's 
I Corps against Lee's left flank 
at dawn on September 17th.  
Moving into a cornfield, Hooker
engaged Stonewall Jackson's 
forces and eventually forced 
them out.  Advancing out of the
cornfield, Hooker's winded 
corps was hit hard by Hood's 
fresh Confederate division, 
sending the Union command 
racing back through the 
trampled cornstalks.

The chewed up soldiers of 
Jackson's three divisions 
stopped in the West Woods to 
regroup - they would not get 
much relief.  Mansfield's Union
XII Corps came out of the East 
Woods, swept across the 
cornfield, and into the West 
Woods and Jackson.  Soon, the 
Union II Corps and two fresh 
Confederate corps joined the 
fray.  Taking fire from three 
sides the Union troops were 
forced to withdraw after taking
2,200 casualties in 20 minutes 
of fierce fighting.

Meanwhile in the center, two 
Union corps assaulted Hill's 
veterans defending a sunken 
farm lane.  For three hours 
Union troops assaulted Hill's 
veterans, prevailing only when 
a misunderstood order opened a 
gap in the Confederate line.  
McClellan, having grown more 
and more cautious, refused 
every request by his 
subordinates to commit reserves
to exploit the opening.

On the Union left, Burnside's 
IX Corps was slowly advancing. 
By three in the afternoon, it 
looked as if he was on his way 
to Sharpsburg and a Union 
victory.  Suddenly Hill's 
troops came up from the south, 
hit him in the flank, sending 
his shattered corps fleeing 
back to Antietam Creek.  Lee 
had held due to the grit of his
troops and McClellan's 
cautiousness (plus a little 
help from Lady Luck).  

Unfortunately for Lee, it was 
not the decisive win that he 
needed.  Battered and spent, 
Lee pulled back across the 
Potomac and abandoned his 
Maryland plan.
