Kampong Trach is the district that borders Vietnam. The road trip from Kampot to the main town passes though some picturesque rural areas. There is a new side road to Kampong Trach town that skirts the base of Phnom Voar, (where the victims of the 1994 Khmer Rouge kidnappings were held.) These mountain areas of Kampong Trach were one of the last Khmer Rouge holdouts. Kampong Trach town is small and relatively uninteresting.
The area's main attraction is a series of limestone caves and tubes that have been carved into a nearby mountain. The roof of a large cave in the center of a mountain has collapsed, making a small, enclosed jungle. Pagodas and shrines have been built amongst the caves, providing for some excellent photo possibilities. Bring a flashlight and wear good walking shoes. From Kampot, take the Kep road, bear left at the White Horse Monument and follow to Kampong Trach.
After a few kilometers the road changes to badly broken pavement. The side road mentioned above requires a left turn onto a graded dirt road about 7 km past the White Horse Monument. It is not a straightforward route and it may be better if you go with a guide. Set aside the better part of a day for the trip to the caves and back.