Cold Water Spring

Useful Information

Location: Cold Water Springs State Wildlife Area, 2832 Cold Water Creek Rd, Decorah, IA 52101.
15 min/1 km hike from the parking lot.
(43.4415356, -91.9551408)
Open: no restrictions.
Fee: free.
Classification: KarstKarst Spring
Light: n/a
Dimension: L=27,366 m, VR=24 m.
Guided tours: self guided
Photography: allowed
Accessibility: no
Address: Cold Water Spring, Cold Water Springs State Wildlife Area, 2832 Cold Water Creek Rd, Decorah, IA 52101.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1967 cave system behind the spring discovered and first explored.
1967 State of Iowa took exclusive control of the cave and created an artificial entrance into the cave on private land which they leased.
1970 underwater gate installed at the natural spring entrance.
1975 commercialization by the State failed due to lack in funding, lease returned to landowner.
1987 cave designated a National Natural Landmark by the National Park Service.
1989 Minnesota Cave Preserve established by John Ackerman.
2003 Minnesota Cave Preserve expanded to include Cold Water Cave.
2004 artificial entrance into the cave completed.
2006 John Ackerman and Clay Kraus discover new passages.


Cold Water Spring is a karst spring, after which the State Park where it is located was named, and also the huge cave system behind the spring. The Cold Water Cave is more than 27 km long which makes it the longest cave of Iowa. The river from the spring is a tributary of the Upper Iowa River. The water-filled spring issues from the base of a 45 m tall bluff. Although located in the Cold Water Spring State Park, the spring is accessed on a walking trail from the parking lot of the Cold Water Creek Wildlife Management Area, which is adjoining. Its only a 1 km easy walk. There are no restrictions as far as we know, nevertheless we strongly recommend daylight hours.

The karst area is called Driftless Area and extends over Iowa and Minnesota. The area has disappearing streams, blind valleys, sinkholes, caves, and karst springs. The river called Cold Water actually does not spring from the Cold Water Spring, it begins about 5 km to the northwest. But this upper part of the river id dry most of the year, it seems it is in the process of becoming a dry valley. But the Cold Water Spring adds water to the river, so it is perennial from here downstream.

The cave system behind is today accessible through two entrances. The natural entrance through the spring is quite difficult and dangerous, cave diving is required. In 1970, an underwater gate was installed to stop any diving attempts. The first artificial entrance into the cave system was created by the State of Iowa on private land which they leased. They planned to open a show cave but were not able to get the funding. But after they had the lease returned to the landowner, the entrance was not accessible any more. We are not aware why the landowner did not allow cavers to enter through this entrance is unclear, probably the fear of being sued.

The cavers purchased a piece of land and created a cave preserve, and built a second artificial entrance tunnel. A 10-m deep artificial shaft which is stabilized by a concrete tube leads down into the cave system and allows the cavers easier access. However, the cave is not open to tourists or spelunkers. But the story how the artificial entrance was built is interesting.

The windmill with a pump was erected to pump water for the farmer. When they drilled the hole, wind screamed out, a sign that there was a cave blow. But they were not able to enter the cave through the narrow hole. They sent a wooden fence post down the hole. In the 1960s, when the drillers and owners of the windmill were long dead, the cavers discovered the wooden post in the cave. The cavers had traced an eerie banging noise inside the cave. It was the result of the lift rod clattering in the steel pipe of the old windmill. The borehole of the windmill actually intersected the cave. So the cavers purchased the land around the windmill and drilled a hole 25 m south of the windmill. They left the windmill untouched for preservation reasons. They first drilled a 5.25 inch diameter test hole and missed the cave. But with the second attempt they hit the cave. The hole was secured with casing, so it may be used, for example, for an electrical conduit for scientific in-cave equipment. Then the actual shaft was drilled, first with a lower diameter which was then extended to 75 cm. The drill stopped 3 m above the cave and the shaft secured with a conrete tube, then the rest was drilled.

The Minnesota Cave Preserve owns eight preserves in southeast Minnesota and northern Iowa. This covers 45 caves.