Camp Douglas: Located near Chicago, Camp Douglas was one of the largest and most important Union Army training camps during the Civil War. The camp was established in 1861 and eventually housed over 100,000 soldiers. Camp Douglas was also used as a prison camp for Confederate soldiers, and an estimated 12,000 soldiers died there during the course of the war.
Camp Butler: Established in 1861 near Springfield, Illinois, Camp Butler was another major training ground for Union soldiers. The camp was named after General Benjamin F. Butler, who was the commander of the Department of the Gulf during the Civil War.
Camp Fry: Camp Fry was a Union Army camp located near Cairo, Illinois, at the confluence of the Mississippi and Ohio Rivers. The camp was established in 1861 and served as a staging area for operations in the Western Theater of the Civil War. Camp Fry was also used as a hospital and a prison camp for Confederate soldiers.
Camp Logan: Camp Logan was established near Springfield, Illinois, in 1864 as a training ground for new recruits in the Union Army's 17th Corps. The camp was active until the end of the war and an estimated 100,000 soldiers were trained at Camp Logan during the course of the war.