Alton is a city on the Mississippi River in Madison County, Illinois, United States, about 15 miles (24 km) north of St. Louis, Missouri. The population was 27,865 at the 2010 census. It is a part of the Metro-East region of the Greater St. Louis metropolitan area in Southern Illinois. It is famous for its limestone bluffs along the river north of the city, for its role preceding and during the American Civil War, and as the hometown of Robert Wadlow, the tallest man known. It was the site of the last Abraham Lincoln and Stephen Douglas debate in October 1858. The former state penitentiary here was used during the war to hold up to 12,000 Confederate prisoners of war.
The city has been labeled "The most haunted city in America" by paranormal enthusiasts, due to its claimed haunted hot spots, such as McPike Mansion and other structures. Most were built on foundations of stone taken from the former Civil War prison after it was abandoned. Confederate prisoners had suffered severe overcrowding, and many died during a smallpox epidemic. The city holds regular "ghost tours" and has been visited by television crews hoping to film proof of the paranormal.
The Alton area was home to Native Americans for thousands of years before the 19th-century founding by European Americans of the modern city. Historic accounts indicate occupation of this area by the Illiniwek or Illinois Confederacy at the time of European contact. Earlier native settlement is demonstrated by archaeological artifacts and the famous prehistoric Piasa bird painted on a cliff face nearby. The image was first written about in 1673 by French missionary priest Father Jacques Marquette.