Nightfall in Antietam

At 10 am Union Gen. Ambrose Burnside's Ninth Corps began its 
assaults on the Lower Bridge. By 1 pm Federals had driven the 
Confederates from the bluff overlooking the creek. 
The battle ended about 6 pm. 
Of nearly 100, 000 soldiers engaged in battle, 
about 23,000 were killed, wounded, or missing...