St. John Mine

Perrot's Snake Cave

Useful Information

Location: In Potosi. North of Dubuque, on the eastern shore of the Mississippi.
Open: MAY to OCT Thu-Tue 9-17. [2007]
Fee: Adults $4.50, Children (6-12) $2.25.
Groups (10+): 10% discount.
Tax 5%.
Classification: SpeleologyKarst cave MineLead Mine
Light: LightIncandescent Electric Light System
Dimension: L=68 m, T=10 °C.
Guided tours:
Bibliography: J. W. Whitlow, W. S. West (): Geology of the Potosi Quadrangle, Grant County, Wisconsin, and Dubuque County, Iowa, pb, 4 plates (in pocket), 1 fig.
Address: St. John Mine, P.O. Box 155, 129 South Main Street, Potosi, WI 53820, Tel: +1-608-763-2121. 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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1690 the natives showed Nicholas Perrot the cavern.
1827 the Winnebago Peace Treaty was signed, start of mining.
1827-1829 mine was the most productive in the area.
1870s mine worked out and closed.
1969 opened to the public.


Despite its name, St. John Mine is originally a natural cave. But in this cave rich veins of lead ore were found and mined during the 19th century.

This cave was shown to Nicholas Perrot, the famous french explorer, by native Indians in 1690. He explored the cave and discovered beautiful formations and rich ore veins. He named the cave Snake Cave and the valley it was overlooking Snake Hollow. From now on the natives and the early French settlers worked the mine now and then, as they needed.

In 1827, after the Winnebago Peace Treaty was signed, the area was inhabited by pioneers. Among them was Willis St. John, who claimed this site his own and immediatly started to mine the cave more intensive. In the first two years the mine produced more than 200 tons of ore. This made this mine the most productive in the whole area. The village of Potosi was a pure miners village which sprang up around the mine.

But Willis St. John then made a series of bad investments and was forced to sell his mine. The new owners were Henry Massey and Nelson Dewey. Nelson Dewey is famous, because he became later Wisconsin's first governor.

The mine was closed in the 1870s, when it was worked out. It was reopened in 1969 as a show cave or show mine.