On what date did the Battle of Gettysburg begin?

The Battle of Gettysburg began on July 1, 1863, when Confederate and Union forces unexpectedly collided near Gettysburg, Pennsylvania. The opening engagement grew from the movements of Robert E. Lee’s Army of Northern Virginia during its invasion of the North and Union efforts to locate and concentrate against it.

Union cavalry under Brigadier General John Buford encountered Confederate infantry west of town during the morning. Buford’s dismounted cavalry delayed the advance until infantry from the Union I Corps arrived. Fighting then spread across McPherson Ridge, Seminary Ridge, and the northern approaches to Gettysburg as additional corps reached the field.

The battle lasted three days, from July 1 through July 3. On the first day, Confederate forces eventually pushed Union troops through Gettysburg to Cemetery Hill and the surrounding heights. The Union army held those positions on July 2 and July 3, surviving attacks on both flanks and the center. The date is sometimes confused with July 4 because Lee’s retreat began around then, but July 4 was the day after the battle’s fighting had ended.