The collapsed cavern
Kampong Trach sits close to the Vietnamese border in the east of Kampot province, where isolated limestone karsts rise abruptly from otherwise flat rice country.
The main attraction is Phnom Kampong Trach, a hill riddled with caves. At its centre the roof of a large cavern collapsed at some point in the geological past, leaving a roughly circular open chamber ringed by sheer walls, with vegetation hanging down and daylight pouring in. You reach it through a short, dark passage from the pagoda at the base.
What else is there
A network of smaller caves runs off the main chamber, some holding shrines and reclining Buddha figures. Local children offer to guide visitors through with torches for a small tip, and the guiding is genuinely useful — the passages are dark and the floors uneven.
Some caves were used for shelter during the conflict years, and the guides will point out where.
Wat Kirisan at the foot of the hill is the starting point for most visits.
Visiting
Kampong Trach is about thirty-five kilometres east of Kampot town and is usually combined with Kep in a single day trip by tuk-tuk or hired scooter.
Wear shoes with grip — the limestone is slick where water has run over it — and bring a torch rather than relying on a phone. Modest dress is appropriate at the pagoda.