He was practicing law in Warm Springs, Virginia, when the American Civil War began.

He joined the Confederate Army and was elected major of the 13th Virginia Infantry Regiment in May 1861.

For many years, William Terrill was the prosecuting attorney for Bath County, Virginia.

[2] Starting in 1860 and when the Civil War began, he was practicing law in Warm Springs, Virginia.

[8] James Barbour Terrill had already been nominated to the grade of brigadier general when he was killed at the Battle of Bethesda Church.