In July, 1861, the 13th South Carolina Infantry was formed at camp Lightwoodknot Springs, near Columbia, from ten companies from counties in the upstate of South Carolina. O. E. Edwards was elected Colonel of the 13th. In the autumn the 13th was ordered to the coast where it was placed under the command of Brigadier-General Maxcy Gregg along with the 12th and 14th S.C. They remained on the coast until April, 1862 when they were ordered to Virginia.

The 1st South Carolina and Orr's Rifle Regiment were then attached to the brigade around the 30th of April, 1862. One month later the 13th was heavily engaged at the battles of Cold Harbor and Frazier's Farm. After this campaign, Gregg's brigade camped a few miles south of Richmond where many men contracted typhoid fever or dysentery due to the conditions and location of the camp.

At the beginning of August, the 13th along with Gregg's brigade were on the march after being assigned to Jackson's army. The 13th was placed on the right of the regiment upon arriving at Manassas Junction on the morning of August 29. The 2nd battle of Manassas tested the 13th severely when they held their ground in an attack from Popes forces after they exhausted their ammunition. Colonel Edwards was wounded during this battle.