The Second Battle of Bull Run or Battle of Second Manassas was fought August 28–30, 1862, in Prince William County, Virginia, as part of the American Civil War. It was the culmination of the Northern Virginia Campaign waged by Confederate Gen. Robert E. Lee's Army of Northern Virginia against Union Maj. Gen. John Pope's Army of Virginia, and a battle of much larger scale and numbers than the First Battle of Bull Run fought on July 21, 1861, on the same ground.

The Army of Northern Virginia was the primary military force of the Confederate States of America in the Eastern Theater of the American Civil War. It was also the primary command structure of the Department of Northern Virginia. It was most often arrayed against the Union Army of the Potomac.