Snippet from Wikipedia: Battle of Gettysburg

The Battle of Gettysburg (locally ) was a three-day battle in the American Civil War fought between Union and Confederate forces between July 1 and July 3, 1863, in and around Gettysburg, Pennsylvania. The battle, which was won by the Union, is widely considered the Civil War's turning point, ending the Confederacy's aspirations to establish an independent nation. It was the Civil War's bloodiest battle, claiming over 50,000 combined casualties over three days.

In the Battle of Gettysburg, Union Major General George Meade's Army of the Potomac defeated attacks by Confederate General Robert E. Lee's Army of Northern Virginia, halting Lee's invasion of the North and forcing his retreat.

After his success at Chancellorsville in Virginia in May 1863, Lee led his Confederate forces through Shenandoah Valley to begin the Gettysburg Campaign, his second attempted invasion of the North. With Lee's army in high spirits, he intended to shift the focus of the summer campaign from war-ravaged Northern Virginia in the hopes of penetrating as far as Harrisburg, Pennsylvania or Philadelphia, which he hoped would convince northern politicians to abandon their prosecution of the war. President Abraham Lincoln initially prodded Major General Joseph Hooker to move his Union forces in pursuit of Lee, but relieved Hooker of his command just three days before the battle, replacing him with Meade.

On July 1, 1863, as Lee's forces moved on Gettysburg in the hopes of destroying the Union Army, the two armies initially collided, and the battle commenced. Low ridges to the northwest of Gettysburg were initially defended by a Union cavalry division under Brigadier General John Buford, and soon reinforced with two corps of Union infantry. Two large Confederate corps assaulted them from the northwest and north, however, collapsing the hastily developed Union lines, leading them to retreat through the streets of Gettysburg to the hills just south of the city.

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