The American Civil War saw extensive use of horse-mounted soldiers on both sides of the conflict. They were vital to both the Union Army and Confederate Army for conducting reconnaissance missions to locate the enemy and determine their strength and movement, and for screening friendly units from being discovered by the enemy's reconnaissance efforts. Other missions carried out by cavalry included raiding behind enemy lines, escorting senior officers, and carrying messages.
In the first half of the war, the Confederates enjoyed the advantage in cavalry, not least because most of the experienced cavalry officers from the Regular Army had chosen to side with the Confederacy. Notable Confederate cavalry leaders included J. E. B. Stuart, famed for literally riding rings around the Union's Army of the Potomac, and Nathan Bedford Forrest, who caused havoc with Union supply lines.
The Battle of Brandy Station in 1863 is considered the point by which Union cavalry proved itself equal to the Confederates, and onward through the second half of the war they continued to improve. This was exemplified by Benjamin Grierson's brilliant deception tactics in the Mississippi valley, and Philip Sheridan's aggressive movements while in command of the Army of the Shenandoah at the end of the war in Virginia.
Cavalry units proved highly expensive to maintain, and unscrupulous agents would often exploit shortages by supplying defective animals at exorbitant prices. The Union benefited from the creation of tighter regulations and a centralized acquisition and distribution system which ensured its forces remained mounted throughout the war. Conversely, the Confederacy's system of each soldier supplying their own horses resulted in the degradation of its cavalry units as horses became harder to obtain.