New Jersey also responded by sending troops to Pennsylvania. The War Department created the Department of the Susquehanna, commanded by Maj. Gen. Darius N. Couch, to coordinate defensive efforts in Pennsylvania. Pittsburgh, Harrisburg, and Philadelphia were considered potential targets and defensive preparations were made. In Harrisburg, the state government removed its archives from the town for safekeeping. In much of southern Pennsylvania, the Gettysburg campaign became widely known as the "emergency of 1863". The military campaign resulted in the displacement of thousands of refugees from Maryland and Pennsylvania who fled northward and eastward to avoid the oncoming Confederates, and resulted in a shift in demographics in several southern Pennsylvania boroughs and counties. Although a primary purpose of the campaign was for the Army of Northern Virginia to accumulate food and supplies outside of Virginia, Lee gave strict orders (General Order 72) to his army to minimize any negative impacts on the civilian population. Food, horses, and other supplies were generally not seized outright, although quartermasters reimbursing Northern farmers and merchants using Confederate money were not well received. Various towns, most notably York, Pennsylvania, were required to pay indemnities in lieu of supplies, under threat of destruction. During the invasion, the Confederates seized up to 1,000 northern African Americans, a few of whom were escaped fugitive slaves but most were freemen. They were sent south under guard into slavery. Ewell's corps continued to push deeper into Pennsylvania, with two divisions heading through the Cumberland Valley to threaten Harrisburg, while Jubal Early's division of Ewell's Corps marched eastward over the South Mountain range, occupying Gettysburg on June 26 after a brief series of skirmishes with state emergency militia and two companies of cavalry. Early laid the borough under tribute but did not collect any significant quantities of supplies. Soldiers burned several railroad cars and a covered bridge, and they destroyed nearby rails and telegraph lines. The following morning, Early departed for adjacent York County. The brigade of Brig. Gen. John B. Gordon of Early's division reached the Susquehanna on June 28, where militia guarded the covered bridge at Wrightsville. Gordon's artillery fire caused the well-fortified militiamen to retreat and burn the bridge. Confederate cavalry under the command of Brig. Gen. Albert G. Jenkins raided nearby Mechanicsburg on June 28 and skirmished with militia at Sporting Hill on the west side of Camp Hill on June 29. The Confederates then pressed on to