In many ways, the story of Camp Douglas outside of Chicago is the story of the Civil War itself. The camp got its start as a brand new facility filled with men ready to fight a war that most on both sides believed would last only a few months. However, as the war went on, the facilities were overwhelmed by the sheer scale of the damage and the massive numbers of people involved. In the first few years of the war, the kind of total war practiced by Grant and Sherman in 1864 was unthinkable, and the two sides liberally conducted prisoner exchanges and paroled prisoners based solely on their word. As time passed, however, bitterness hardened between the two sides, and the war aims changed as the North looked for new strategies to finally subdue the South. The resulting chain of events led to the horrors of Civil War prison camps.

During the Civil War, armies took many soldiers captive, but they also captured some civilians as well, such as sutlers, nurses, teamsters, and other service personnel. In addition, both the Union and the Confederacy imprisoned deserters, sympathizers with the enemy, traitors, and draft dodgers. The numbers cited vary somewhat, and often, precise numbers should be regarded with caution because the official numbers do not account for everyone. One somewhat authoritative total is that Confederates confined 7,092 Union officers and 179,091 enlisted men in prison camps, along with 1,962 civilians, for a total of 188,145 (Stack 3). By comparison, the Union captured 35,782 officers, 426,852 enlisted men, and 13,535 Confederate civilians, but this total is misleading because it includes the troops that surrendered when the war ended, including the commands of Robert E. Lee, Joseph E. Johnston, Richard Taylor, and Edmund Kirby Smith. Almost all the troops who surrendered at the end of the war were immediately paroled and allowed to go home.