1863 – American Civil War: The Battle of Gettysburg begins
. The Battle of Gettysburg was fought July 1–3, 1863, in and around the town of Gettysburg, Pennsylvania, by Union and Confederate forces during the American Civil War. The battle involved the largest number of casualties of the entire war and is often described as the war's turning point. Union Maj. Gen. George Meade's Army of the Potomac defeated attacks by Confederate Gen. Robert E. Lee's Army of Northern Virginia, ending Lee's attempt to invade the North. Lee led his army on a torturous retreat back to Virginia. Between 46,000 and 51,000 soldiers from both armies were casualties in the three-day battle, the most costly in US history.