Civil War units were organized groups of soldiers that fought for either the Union or the Confederacy during the American Civil War (1861-1865). These units varied in size and structure, including infantry, cavalry, and artillery. Each unit was typically composed of several companies, which were further divided into smaller squads. The most common unit was the regiment, usually consisting of about 1,000 soldiers. Regiments were often named after their state or the leader, such as the 54th Massachusetts Infantry. Other units, like the 1st U.S. Cavalry, specialized in different types of warfare, contributing to the diverse strategies employed during the conflict.