Johnson's Island Civil War Prison, in operation from 1862 to 1865, served as a vital depot for the confinement of Confederate prisoners of war during much of the American Civil War. It was one of 65 such facilities in which the United States and Confederate governments held hundreds of thousands of military prisoners during the war. Civil War prisoner-of-war camps and stockades have been said to illustrate man's inhumanity to man better than anything else in 19th century warfare.