Andersonville National Historic Site began as a stockade built about 18 months before the end of the U.S. Civil War to hold Union Army prisoners captured by Confederate soldiers. Located deep behind Confederate lines, the 26.5-acre Camp Sumter (named for the south Georgia county it occupied) was designed for a maximum of 10,000 prisoners. At its most crowded, it held more than 32,000 men, many of them wounded and starving, in horrific conditions with rampant disease, contaminated water, and only minimal shelter from the blazing sun and the chilling winter rain. In the prison’s 14 months of existence, some 45,000 Union prisoners arrived here; of those, 12,920 died and were buried in a cemetery created just outside the prison walls.
Camp Douglas was one of the largest Union army prisoner of war camps, to hold Confederate soldiers taken prisoner during the War. Based south of Chicago on the prairie, it was also used as a training and detention camp for Union soldiers. The Union Army first used the camp in 1861 as an organizational and training camp for volunteer regiments. It became a prisoner-of-war camp in early 1862. Later in 1862 the Union Army again used Camp Douglas as a training camp. In the fall of 1862, the Union Army used the facility as a detention camp for paroled Union Army prisoners pending their formal exchange for Confederate prisoners.
Camp Douglas became a permanent prisoner-of-war camp from January 1863 to the end of the war in May 1865. In the summer and fall of 1865, the camp served as a mustering out point for Union Army volunteer regiments. The camp was dismantled and the movable property was sold off late in the year. In the aftermath of the war, Camp Douglas eventually came to be noted for its poor conditions and death rate of between seventeen and twenty-three percent. Some 4,275 Confederate prisoners were known to be reinterred from the camp cemetery to a mass graves in what is known today as Lincoln Park.