Joliet

Alton Military Prison Site in Alton, Illinois

Alton, Illinois's State Penitentiary officially opened in 1833, making it the first state prison in Illinois. It was used to incarcerate convicted criminals from across the state and later served as a military prison. During the Civil War, the facility became the Alton Military Prison and was used to hold Confederate prisoners of war. More than 11,000 Confederate soldiers were held there before…