Giant City State Park is an Illinois state park on 4,000 acres in Jackson and Union Counties, Illinois, United States. Illinois acquired more than 1,100 acres in 1927, and dedicated the park as Giant City State Park. A lodge and visitor center welcome state park guests. Giant City State Park is a popular destination in Southern Illinois, and visitors to the park enjoy a number of activities such as hiking, horseback riding, picnicking, and rock climbing.