Ten companies were formed into a regiment commanded by a colonel. Several regiments formed a brigade commanded by a brigadier general. These large units were typically named for their commanding general and were organized for a campaign or as part of a standing army. The Confederate States Army was divided into geographic military districts whose boundaries changed and were reorganized as the war progress. Normally each military district of the CSA maintained a standing army.
Battalions are smaller than regiments.
Many volunteer forces remained battalions throughout the war and did reach regimental strength.