Northern Name for Battle: First Manassas Southern Name for Battle: First Bull Run Location of Battle: Fairfax County and Prince William County, Virginia Date of Battle: July 21, 1861 Northern Commander: Irvin McDowell Southern Commander: Pierre Gustave Toutant Beaureguard Winner: Confederates Northern Troops Involved: 28,450 Southern Troops Involved: 32,230 Northern Casualties: 2,645 Southern Casualties: 1,981 Interesting Facts: This was the second battle of the war.