Spook Cave is a flooded cave in northeastern Iowa, about seven miles west of McGregor, where visitors enter by escorted boat rides through a water-filled passage. Discovered in 1953 and opened to tourism in 1955, it occupies a 93-acre property with a campground and cabins, giving it the feel of a small outdoor resort. The cave lies in Iowa’s Driftless Area, a karst landscape known for caves, sinkholes, disappearing streams, and cold springs rather than glacial landforms. Its tours depend on water levels maintained by a lock and dam, linking its tourist use to the natural hydrology of Bloody Run Creek and the Upper Mississippi.