Bordered by the Federal capital but separated from Virginia and the Confederacy only by the Potomac River, the citizens of Prince George's County found themselves on the front lines of the Civil War. As Maryland's largest slave-owning county, some—including members of the Bowie and Surratt families—joined the Confederacy. Many remained loyal to the Union, losing sons and property for the cause. Three forts in the county were dedicated to the capital's defense: Fort Foote, Fort Washington and Fort Lincoln. This did not prevent Confederate general Jubal Early's troops from invading in July 1864. The Rebel forces blew up rail lines in Beltsville and took the Rossborough Inn near the Maryland Agricultural College—now the University of Maryland, College Park—as their headquarters. "Prince George's County and the Civil War: Life on the Border" charts the course of a community caught in the midst of the bloodiest conflict in American history.