Over 3 million men were mobilized for action during the Civil War. While the majority of soldiers fought in infantry units, cavalry units played an equally important role in the outcome of the war. Infantry units were men fighting on foot, while cavalry units were soldiers on horseback. The many differences in how these two types of units operated are essential parts of military strategy.

Use in Battle

During battle, infantry units were tightly organized and fought in tandem with other infantry regiments. Cavalry units were much more independent and were used less for head to head fighting, and more for disrupting the enemy's maneuvers. Cavalry attacked supply lines, enemy bases and means of communication to make things difficult for their opponent. Infantry units were used mainly for direct attacks against the brunt of the enemy's infantry.

Use on the Offensive

Infantry units were used to attack the main lines of an opposing army, while also using flanking maneuvers to catch the enemy off guard. Cavalry units were much more likely to be used as screens for the infantry, diverting the enemy's attention away from a moving infantry force. The cavalry also used speed on horseback as a means to get closer to the enemy, then dismounted and fought alongside the infantry. Infantry offensive tactics were mainly organized lines of fire, alternating in the "shoot-reload-shoot-reload" style of warfare common at the time.

Use on the Defensive

When on the defensive, infantry units were usually fighting from fortified entrenchments. This method of fighting consisted of allowing the enemy to attack, then using one's own defenses to throw back the enemy advancement. Cavalry units were used to help coordinate a strategic retreat when the battle was lost. Cavalry troops would continue fighting, holding off the enemy long enough for the infantry to get away safely.

Use in Reconnaisance

West Point instructor Dennis Hart Mahan stated that "there is no more important duty for an officer than that of collecting and arranging the information upon which either the general, or daily operations of a campaign must be based." Infantry units performed reconnaissance in small groups of raiders behind enemy lines, gathering intelligence about enemy positions. Large scale reconnaissance was mostly done by cavalry units because of their mobility. Cavalry, which was the "eyes and ears of the army," brought back detailed maps of topography, battlefields and enemy movements. Infantry units typically did not engage in the most vital reconnaissance missions; that was left to cavalry units.