The first major battle of the Civil War was the Battle of Bull Run, fought on July 21, 1861, in Virginia.

Also known as the First Manassas, this battle marked a significant early conflict between Union and Confederate forces. The Union aimed to capture the Confederate capital of Richmond, but the unexpected resilience and counterattacks by Confederate troops led to a decisive Southern victory. The battle shattered the North's hopes for a quick end to the war and showcased the intensity and brutality of the conflict ahead, setting the stage for future engagements.