Crystal Lake Cave

Marcus Cave - Rice's Cave - Linden's Cave

Useful Information

Location: 5 km South of Dubuque on Hwy 52.
(42.433809, -90.620518)
Open: MAY to Memorial Day Sat-Sun 9-17.
Memorial Day to mid-AUG daily 9-18.
Mid-AUG to Labor Day Mon-Fri 11-17, Sat-Sun 9-18.
Labor Day to mid-Oct Mon-Fri 11-17, Sat-Sun 9-17.
Mid-OCT to OCT Sat-Sun 9-17.
Last tour 1 h before closing.
Fee: Adults USD 20, Children (4-11) EUR 8, Children (0-3) free.
Classification: SpeleologyKarst cave Galena Group Limestone.
Light: LightIncandescent Electric Light System
Dimension: T=10 °C, L=6,000 m.
Guided tours: L=1,200 m, D=45 min.
Photography: allowed
Accessibility: no
Bibliography: Roger Kehret (1976): Your Guide to Crystal Lake Cave, published by the author, Chatfield, Minnesota 1976, 20 pp, many B&W photo, SB.
Greg A. Brick (2004): Iowa Underground / A guide to the state's subterranean treasures, Trail Books, Wisconsin. 223 pp, numerous illus. pp 16-18.
Address: Crystal Lake Cave, 6684 Crystal Lake Cave Rd, Dubuque, IA 52003, Tel: +1-563-556-6451. 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.
Please check rates and details directly with the companies in question if you need more recent info.


1868 the miner James Rice discovered Rice's Cave.
the new owner Charles Linden renamed the cave Linden's Cave.
1932 opened to the public by Bernard Markus.
1932 the cave was maintained by Bernard Markus, the son-in-law of Charles Linden. He renamed it Crystal Lake Cave in the late 1930s.
1940 electric light installed.
1944 the cave was owned by Herbert Knockel and his wife Evlyn.
1978 the current owners, James and Doris Rubel took over ownership.
2014 purchased by Julie Rubel, the grandniece of Bernard Markus.


Crystal Lake Cave was discovered by miners in search for lead ore. The area around Dubuque has many mines. At the bottom of a 14 m deep shaft they found a crevice, which was explored by James Rice for 230 m. Since this time the cave was shown to visitors. Today's name was inspired by a 10 m long crystal lake, which is 60 cm deep.

Apart from stairs at the entrance and exit, the cave is formed on one level and is a typical maze cave, formed along cross joints. Each intersection is at a right angle to the main joint. The passages are of uniform dimensions, about two meters high and go with a level floor and in a straight line for some distance. The original miners shaft can be seen at the bottom of the entrance stairs. Speleothem are numerous and there are helictites and aragonite crystals. The tour begins at one end and exits through another, the only stairs are at either end.

Text by Tony Oldham (2004). With kind permission.