Highest number of casualties in a battle on American soil (The American Civil War)
According to Official Guinness Records,
The Battle of Antietam, which took place in Sharpsburg, Maryland, holds the dubious distinction of being the “bloodiest day” of not only the American Civil War, but of American History. Some 23,100 soldiers were killed, wounded or missing after only twelve hours of combat, some hand-to-hand, on September 17, 1862. Union (the North) losses amounted to 12,410 and the Confederates (the South) lost 10,700 men. General Robert E. Lee led Confederate troops while General George B. McClellan commanded the Union contingent. Although neither side won decisively, Lee nevertheless was unable to continue his first invasion of the North (he was later to lead another unsuccessful attack on Gettysburg, Pennsylvania from July 1—July 3, 1863). The battle gave the North much needed momentum and led to President Abraham Lincoln’s Emancipation Proclamation of January 1, 1863, which although it did not free all slaves, was the first step in the abolition of American slavery.