Late in 1861 the Confederates turned Chapman's Mill into a meat curing warehouse and distribution center. Herds of cattle and pigs were enclosed in large pens, and more than two million pounds of Confederate meat were stored on the site. Confederates, retreating south, on March 9, 1862, burned the meat and the mill to keep them from the advancing northern troops. On August 28, 1862 Union General Ricketts was ordered to occupy Thoroughfare Gap to prevent Generals Lee and Longstreet from marching through the Gap and joining Confederate troops gathering for the Second Battle of Manassas. Historians say that if Ricketts had prevailed at the Battle of Thoroughfare Gap, which took place in and around the mill, the Second Battle of Manassas would never have taken place.