Alexander Caverns

Mammoth Spring

Useful Information

Location: Kishacoquillas Valley, 2mi southeast of Milroy. Armagh Township, PA 17084.
(40.696587, -77.559789)
Open: Only after appointment, not on Sundays.
Fee: Only after appointment.
Classification: SpeleologyKarst cave KarstKarst spring,
Light: n/a
Dimension: L=3413m
Guided tours:
Photography: allowed
Accessibility: no
Address: Bald Eagle Grotto, PO Box 71, Cogan Station PA 17728. E-mail:
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.


1926 first exploration by John Spielman and Henry Schmidt.
1929 construction of artificial entrance and opened to the public.
1930 boat tours added.
1959 show cave closed.
1966 cave door broken and cave vandalized.
1986 negotiations to regain access to this cave by the new formed Bald Eagle Grotto.


Alexander Caverns is a former show cave which has long been on our closed caves list. But the cave is explored by the Bald Eagle Grotto and they offer cave trekking tours into the cave. There are no rules except that the visit on Sundays is not possible. So contact the grotto directly on their website.

Mammoth Spring is the third largest spring in Pennsylvania and flows at an average of 53,000 l/m. It is the resurgence of a river cave and there is actually no technical difficulty in entering the cave except for the water. The spring was known and used by settlers, but they obviously never entered the cave behind. The first exploration was in 1926 by John Spielman and Henry Schmidt. They followed the river passage and found a dry section branching off. We guess they also named the cave Alexander Caverns. It seems the development of the cave started immediately, and in 1929 an artificial entrance was constructed, which allowed access to the dry passage. The show cave was opened to the public in the same year, and in the next year a boat ride was added to the cave tour. It is not clear how successful the show cave actually was. It was closed 1959, because the lease on the caverns expired and the landowners chose not to renew. The cave was closed by a door, but at least once the door was broken and the cave vandalized.

Bald Eagle Grotto is a local caving club which was formed in 1986, and immediately started negotiations to regain access to this cave. The wrote a management plan which was accepted by the landowner and since then the cave is explored by the club. Today a total of 3413 m cave passages is surveyed. Only the concrete parts of the tour trail remains, so the cave is now in an almost natural state. The club offers cave trekking tours which are customized to the level of experience. The easiest is probably a walking tour of the dry part and a kayak tour on the river. Helmets, headlamps and additional gear are provided if necessary.