Spook Cave

Spook Hole

Useful Information

Location: Clayton. 11 km west of McGregor, 11 km east of Monona, on U.S. Hwys 18 & 52 .
(43.031695, -91.310835)
Open: MAY to OCT daily 9-17:30, last tour 17.
Fee: Adults USD 14, Children (4-12) USD 10, Children (0-3) free.
Classification: SpeleologyKarst cave SpeleologyRiver Cave
Light: LightIncandescent Electric Light System
Dimension: T=8 °C.
Guided tours: D=40 min., L=800 m.
Bibliography: Roger Kehret (1976): Your Guide to Spook Cave, with photos, maps and description of your tour. 24 pp, illus., published by the author, Chatfield, Minnesota.
Greg A Brick (2004): Iowa Underground / A guide to the state's subterranean treasures, Trail Books, Wisconsin. 223 pp, numerous illus. pp 12-15.
Address: Spook Cave, 13299 Spook Cave Rd, McGregor, IA 52157, Tel: +1-319-873-2144, Fax: +1-563-873-3480. E-mail: contact
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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1953 discovered by Gerald Mielke.


Spook Cave is the source of a tributary to Bloody Run Creek. It is known for a very long time, the early settlers knew the intermittent noises that came out of a tiny opening in the rock.

The first one to explore the cave was Gerald Mielke. He wanted to find out what this hole was and blasted out an opening. He found an underground river.

A lock and dam at the opening of the cave control the level of the water. The tours are done entirely by boat, leaving from a landing outside the cave entering the cave through the artificial entrance tunnel. The aluminim boats are powered by electric motor, which makes the tour a silent and effortles glide through the cave.

Some brochures tell, Spook Cave has America's longest underground boat tour, which may be true. Sometimes they say it's the worlds longest underground boat tour, which is definitely not true. But maybe it is the underground boat tour with the lowest ceiling: the visitors have to duck into the boat at some points of the tour.

Since Gerald Mielke opened the entrance and built the dam, the mysterious intermittent noises have never been heard again. Some say, Mr. Mielke released the spirits. Of course, the geologic explanation would tell about changing water levels and water roaring through narrow passages. But the mysterious explanation about spirits is the reason for the cave's modern name Spook cave.