Khao Phra Viharn, or Preah Vihear in Khmer – and the famous 11th-century Hindu temple itself is 100% Cambodian, whatever various lunatic fringe Thais might claim! (Since most of the local Thais in that part of the kingdom – southern Si Saket Province – speak Khmer anyway they could have just kept the original name instead of the cumbersome Thai translation!?)
The Thai government has seen fit, however, to create a national park out of 130 square kilometres of wooded slopes on the Thai side of the section of the Dandrek Escarpment upon which the temple is situated. Hence the park’s English name – Phra Viharn Mountain National Park, even though Phra Viharn is actually the Thai name of the Khmer temple over the border. Confused!? (Note the temple itself is not part of the national park.)
A bit of a slim excuse for a national park for that matter – there are a couple of minor waterfalls and a cave or two but then the chances are any hill in Thailand is going to have a cave and a waterfall! Any hill in Thailand doesn’t allow for easy visitors’ access to a spectacular 11th-century temple though, (notoriously arduous from the Cambodian side), and so any old hill wouldn’t justify a ticket booth collecting 500 baht (foreign tourists) and 20 baht (? locals), since the location of the park means it’s impossible to reach the temple on the nice smooth sealed Thai road without entering their spurious park!
As you’ve gathered it’s one national park we could easily do without. Apart from a moderately interesting cliff carving on the Thai side, we’re sure that 99% of visitors to the park see nothing except the toilets, car-park and cafes! (That’s $17 at current rates – expensive toilets – and that’s per person!) Fortunately, the roads on the Cambodian side are currently being upgraded so pretty soon it’s going to be easy enough to visit from Siem Reap or Phnom Penh, and anyway at the time of writing the Thai government had closed the temporary crossing point at the temple because of the on-going border dispute!