(Sept. 17, 1862) Decisive and bloody battle of the American Civil War that halted the Confederate advance on Maryland.
Following victory in the Second Battle of Bull Run , Gen. Robert E. Lee moved his troops into Maryland with an eye to capturing Washington, D.C. They were stopped by Union troops under George B. McClellan at Antietam Creek, Md. Confederate casualties numbered some 13,700, and Union losses were about 12,400. McClellan was criticized for allowing Lee's forces to retreat to Virginia, but the victory encouraged Pres. Abraham Lincoln to issue a preliminary Emancipation Proclamation .