Organization of an Army

Infantry Company Each company is comprised of 100 men. The make up of the company is as follows: 2 platoons, 4 sections, 8 squads. Commissioned Officers 1 Captain, 1 1st Lieutenant, 1 2nd Lieutenant. The Captain commanded the company while the 1st and 2nd Lieutenants commanded the platoons. If the company were to split up the Captain would take 1 platoon and the 1st Lieutenant the other. Non-Commissioned Officers 1 1st Sergeant, 4 Sergeants, and 8 Corporals and 2 Musicians. The squads are led by a Corporal, sections are led by a Sergeant, the 1st Sergeant runs the entire company.

Regiment and Battalion Each Regiment is comprised of 10 Companies. Approx. 1000 men. Commissioned Officers Colonel, Lieutenant Colonel, Major, Adjutant {Lt.}, Surgeon {Major}, Asst. Surgeon {Capt.}, Quartermaster {Lt.}, Commissary {Lt.}. Non-Commissioned Officers Sergeant Major, and Quarter Master Sergeant. Organizations containing less than 10 companies {usually 4-8 companies} were called Battalions. These Battalions were usually commanded by a Major or Lieutenant Colonel. The new regular regiments used a different organization. They were comprised of 8 companies to a battalion and 2 battalions to a regiment. This gave the new regular regiment 16 companies. They primarily fought as battalions rather than regiments, however if the 2nd battalion could not be recruited up to strength they would fight as a regiment.

Brigade Each Brigade is comprised of 3 to 6 regiments, and would be commanded by a Brigadier General. The Confederate army usually used more regiments than the Union, actually having larger brigades. Also Artillery could be attached to a brigade. The number of staff officers would vary among the brigades. Approx. 4,000 men.

Division Divisions are comprised of 2 to 6, brigades and would be commanded by a Major General. The Union army usually had 3 to 4 brigades per division, and the Confederate army 4 to 6 per division. If the Confederate regiments were the same size as their Union counterpart their divisions could be almost twice the size of the Union divisions. Artillery and Cavalry could also be attached to the division. The number of staff officers would also vary among the divisions. Approx. 12,000 men

Corps A Corps is comprised of 2-4 Divisions, and is commanded by a Major General {Lieutenant General in the Confederate army}. Usually the Union army had 2-3 divisions per corps and the Confederate army had 3-4 divisions. The number of staff officers would vary among the Corps. Approx. 36,000 men

Armies An army is comprised of a number of Corps. The number of Corps would vary depending on the manpower needed to secure and defend a Department. {A Department is a pre-determined geographic area usually named after a landmark or body of water.... ie...Department of the Potomac} An Army was commanded by a Major General in the north and usually by a Full General in the south. Again the number of staff officers would vary among armies.

Cavalry Company or Troop Basically the same makeup as an infantry company. If the company fought dismounted 1 out of every 4 troopers would stay behind with the horses. Battalion and Regiment 12 troops or companies makeup a regiment. Each regiment is commanded by a Colonel. A Confederate Cavalry regiment generally consisted of 10 companies or troops. Union Regulars had a different arrangement, 2 troops form a squadron, 2 squadrons form a battalion, and 3 battalions form a regiment. Also 4-8 companies of volunteer cavalry were called battalions. Brigade, Division, Corps At the beginning of the war each Union cavalry regiment was assigned to an infantry division, while the Confederate cavalry was brigaded together. The Union soon adopted the brigade organization for it's cavalry. As the war went on both sides started to form their cavalry in divisions, this was also a Confederate innovation that the Union adopted. Finally the union began to form it's cavalry as corps. The Confederate army this time would follow the Union and later form their cavalry as corps.

Artillery Battery A battery is comprised of 4-6 guns and is commanded by a captain. There are 4 lieutenants, 12 noncommissioned officers, and 120 privates. Typically the Union had 6 guns per battery and the Confederates 4 guns per battery. A battery was divided into gun crews of about 20 men and into sections of 2 gun crews with 2-3 sections per battery. Gun crews were commanded by a sergeant and sections were commanded by a lieutenant. Battalion or Brigade At the onset of the war both sides assigned a battery to each infantry brigade, with a reserve under the army commander. In mid 1862, both sides began organizing 3-4 batteries as battalions {Confederate} or brigades {Union} and were commanded by a colonel, lieutenant colonel, or major. Artillery Reserve It was typical for each infantry division to have an artillery battalion attached after 1862. Also each corps or army had a reserve of 2 to 5 battalions. A division's artillery would usually fight along side it's infantry in support, and the corps reserve would form the massed batteries. Reserve artillery was commanded either by a brigadier or colonel.

Engineers Engineer regiments were formed on both sides during the war. Their organization was similar to that of the infantry regiment. These men were experts at the art of building forts, bridges, and entrenchments. They would fight as infantry if needed but spent the majority of the war in construction. Sharpshooters Union and Confederate armies both had special infantry units deemed "Sharpshooters". The southern units tended to act as independent companies while the Union forces raised two regiments. These were Hiram Berdan's 1st U.S. and 2nd U.S. sharpshooters. They normally operated as skirmishers, although they did also roam around independently of other forces to find good positions on the field to shoot enemy officers.