The Alton Confederate Cemetery is considered one of the most haunted locations in Alton, Illinois, due to its tragic history and the high number of Civil War soldiers who died in the nearby Alton Military Prison. The suffering and death caused by disease and poor conditions are said to have left a residual energy that still affects the area. The cemetery holds the remains of Confederate soldiers who were imprisoned at the former Illinois state penitentiary, which was converted into a Union military prison during the Civil War. The intense emotion and suffering associated with these deaths are believed to be the primary source of the paranormal activity in the area. Visitors often report seeing shadowy figures and unexplained shapes in the cemetery, particularly around the large central monument that lists the names of the dead. Cries, groans, and other disembodied voices have been heard echoing across the cemetery grounds. These are sometimes interpreted as the last agonized sounds of the dying prisoners. Sudden, localized drops in temperature are frequently reported, even on warm days. Some believe this signifies a spirit passing through or attempting to manifest. In addition to active hauntings, some experiences are thought to be "residual" in nature. These are like replays of past events, such as soldiers marching or the sounds of musket fire, reliving the tragedy of the prison. Many visitors report a general sense of unease, foreboding, or being watched while in the cemetery. Others feel a strong sense of sadness or empathy for the soldiers buried there, a common phenomenon in places with a history of great suffering.