The Union army established a prisoner of war depot on Johnson's Island from April 1862, to September 1865. This cemetery holds the graves of 206 Confederate soldiers who died while imprisoned here. Individual home-owners privately own the remainder of the island. The nearby museum exhibits images, artifacts, letters, and other materials covering the island's history, including the forty months that the POW depot existed.
Camp Chase, the largest camp in the area, was used for training Union soldiers. Later, it served as a prison for captured Confederates. Camp Chase is one of the largest Confederate cemeteries in the north, with over 2,000 prisoners buried there.