The Battle of Antietam is known as the bloodiest day in American history during the Civil War. The battle took place near Sharpsburg, Maryland on September 17, 1862 between the Union Army of the Potomac under the command of General George McClellan and the Confederate Army of Northern Virginia led by General Robert E Lee. The Battle of Antietam is known as the bloodiest day in American history because there was a casualty every 2 seconds for the 12 hours that the battle lasted for a total of 23,000 men killed or wounded in the fields, woods and dirt roads, and changed the course of the war. Civil war. (Bowman, 2012)This was Robert E. Lee's first invasion of the North. After his recent victories over the Union during the Battles of Seven Days and Second Manassas, Lee wanted to continue his good fortunes with an attack on Maryland. (Antietam, 2013) General Lee planned to bring his troops to pressure Northern politicians to liberate Maryland so he could add another state to the Confederate cause, with the hopes of defeating the union on Northern soil and forcing European countries to support the Confederation. However, he was intercepted by General McClellan who marched 87,000 Union soldiers from Washington. At dawn on September 17, the Battle of Antietam began after General Robert E. Lee marched 45,000 soldiers from northern Virginia to invade the North with the hope of defeating the Union. General Lee with half of General McClellan's soldiers decided to split his forces by sending half of his soldiers south to capture Harpers Ferry under the command of General Stonewall Jackson and the other half to take Hagerstown. Once Harpers Ferry was captured, General Jackson was to meet again with General Lee at Hager...... center of card...... l war academy.com: http://www.civilwaracademy. com/Antietam.htmlBattle of Antietam. (2009). Retrieved from History.com: http://www.history.com/topics/american-civil-war/battle-of-antietamBowman, T. (2012, September 17). Antietam: A Wild Day in American History. Retrieved from NPR: http://www.npr.org/2012/09/17/161248814/antietam-a-savage-day-in-american-historyHeisey, C. (n.d.). Antietam. Retrieved from Civil War Trust: http://www.civilwar.org/battlefields/antietam.html?tab=factsMitchell, B. (2007, September 06). The Antietam battlefield still contains valuable lessons. Excerpt from Sound off: http://www.ftmeadesoundoff.com/news/4665/antietam-battlefield-still-holds-valuable-lessons/Union troops discover rebels' Antietam battle plan. (2014). Excerpt from The History Channel website: http://www.history.com/this-day-in-history/the-union-discovers-lost-order.