Spider Hill is an annual Halloween event held at Three Sisters Park in Chillicothe, Illinois, USA, and touted by the organizers as the number one haunted house attraction in Central Illinois.
Spider Hill was launched in 1999 by the local Optimist Club and Three Sisters Park and featured three main attractions: The Massacre Mansion, The Haunted Express haunted hayride and The Trail of Terror, which walks visitors through the forest. Sponsors of the event remind visitors of the legend of Spider Hill and the event's namesake where 23 individuals died at the site during World War I from poisonous spider bites. The event is run entirely by volunteers, starting with 60 in 2000 and increasing to 165 in 2007. Volunteers participate in organized workshops to share scaring techniques. The last attendance figures released were in 2004, when 20,000 visitors went through the various attractions during the October weekends and Halloween night. Event volunteers or actors reveal the biggest screams result from encounters with terrifying clowns, causing a grown man to faint twice in 2003 and another to spit at the circus specter for scaring his girlfriend.