The Old Idaho State Penitentiary is described as a heavily haunted site, with visitors and staff reporting physical sensations like being touched or grabbed, visual phenomena such as shadow figures and doors slamming, and auditory experiences including running, screaming, and disembodied laughter. These paranormal events are attributed to the more than 129 inmates who died on-site from various causes like murder, suicide, disease, and accidents, and tend to occur in specific areas like "House Three" and "House Four," though they can happen anywhere on the grounds. The site has been featured on several paranormal TV shows and is known for the energy visitors feel. Visitors and staff have heard sounds of running, screaming, laughing, and even a party when they were alone. Shadow figures are frequently seen, particularly in areas known as House Three and House Four. Doors have been observed slamming shut on their own. People have reported feeling touched or grabbed in empty buildings. Paranormal investigation groups have recorded electronic voices answering questions and stating their names. While paranormal activity has been reported throughout the property, it is most common in "House Three" and "House Four," where staff and visitors have seen shadow figures and heard noises. Over 129 prisoners died at the penitentiary during its years of operation. The causes of death included murders, suicides, industrial accidents, and disease. The building's history of scandals, executions, and escapes contributes to its reputation.