Video: Sept. 17, 1862 (part three at 52:20)

(Wednesday, September 17, 1862, 12:30 p.m.-5:30 p.m., local time, part of the Maryland Campaign during the American Civil War) — The third of three battles in the Battle of Antietam, the bloodiest battle day in U.S. history (located near Maryland’s Antietam Creek at Sharpsburg), began this afternoon as Union Gen. Ambrose Burnside attacked Gen. James Longstreet’s troops across a stone bridge that came to bear Burnside’s name.

The Yankees crossed the creek, but a Confederate counterattack brought any further advance to a halt.

The first major battle in the war to take place on Union soil was over by 5:30 p.m.Losses for the day were heavy on both sides. The Union had 12,401 casualties with 2,108 dead.

Confederate casualties were 10,318 with 1,546 dead. This represented 25% of the Federal force and 31% of the Confederate. More Americans died on September 17, 1862, than on any other day in the nation’s military history.

Although considered a tactical draw between the Army of the Potomac and the much smaller Army of Northern Virginia, the Battle of Antietam, marked the end of Confederate General Robert E. Lee’s invasion of the North.