The First Battle of Bull Run (First Manassas) was the initial major engagement of the US Civil War, fought in July 1861 near Manassas, Virginia. It shattered early hopes for a quick, decisive conflict by exposing both the inexperience of forces and the brutal reality of war. The confrontation ended in a Confederate victory, revealing deep organizational and tactical challenges for both sides. This battle set the stage for a protracted and more destructive conflict, emphasizing that the war would be long and painful for the nation.