The Battle of Blackburn's Ford took place on July 18, 1861, in Prince William County and Fairfax County, Virginia, as part of the Manassas Campaign of the American Civil War. On July 16, 1861, the untried Union army under Brig. Gen. Irvin McDowell, 35,000 strong, marched out of the Washington, D.C., defenses to give battle to the Confederate army, which was concentrated around the vital railroad junction at Manassas. Moving slowly, they rea...