Manassas National Battlefield Park is a unit of the National Park Service located in Prince William County, Virginia, north of Manassas that preserves the site of two major American Civil War battles: the First Battle of Bull Run, also called the Battle of First Manassas, and the Second Battle of Bull Run or Battle of Second Manassas. It was also where Confederate General Thomas J. Jackson acquired his nickname "Stonewall". The park was established in 1936 and listed on the National Register of Historic Places on October 15, 1966.