These are marble caves, which is unusual in itself, and the whole system was cut by one stream. Trout Brook runs through Pottersville, New York, disappears underground through several of the caves, and resurfaces about 660 feet away at a pothole known as the Clamshell.
There are eleven caves in the park. The headline is Stone Bridge Cave, whose entrance measures 160 feet wide and 33 feet tall and is advertised as the largest marble cave entrance in the eastern United States, which is a claim that survives contact with actually standing in front of it. The others are smaller and each has its own character: Noisy Cave holds a loud underground waterfall, and there are Lost Pool Cave, Kelly's Slide Cave and Echo Cave among them.
The caves are geologically young, and it shows. Apart from the huge entrance of Stone Bridge Cave, most consist of short passages with very few speleothems, because there has not been time for much to grow. Many of them end in sumps, where the passage runs below the water table and simply fills. What the park has instead of decoration is moving water: potholes drilled into marble by stones spinning in the current, whirlpools and waterfalls along the brook.
The self guided trail follows Trout Brook past the caves and the karst features, and the site is above ground rather than a lamp lit walk through darkness, which makes it a very different sort of visit from a decorated show cave.
It sits in the southern Adirondacks near Pottersville, and it is seasonal. In winter the operators run guided trips onto the frozen brook and into ice filled passages, which is when the place is at its strangest.
Check the calendar before you drive, because this one is shut more than it is open. The operator's own notice reads: park is CLOSED mid October to mid December, March to late May, and Christmas Day. The summer self-guided tour runs daily from 15 May to 7 September 2026, nine until half four for last tickets, and the autumn tour from 8 September to 18 October, ten until half three. The winter snowshoe tour, the one that takes you onto the frozen brook, runs ten until half two when it runs at all and is currently closed for the season.
Other places on the map within a couple of hours.
