Khao Phra Viharn National Park

Khao Phra Wihan National Park protects the Thai-side approach to Prasat Preah Vihear, the 11th-century Khmer temple whose ruins the International Court of Justice awarded to Cambodia in 1962. The park itself — the red sandstone cliff, the surrounding dry evergreen and dipterocarp forest, and the Pha Mor E Daeng viewpoint — sits squarely in Kantharalak district, Si Sa Ket, about 98 km south of Si Sa Ket town.

Watch out: Since a border clash between Thai and Cambodian forces near this frontier in May 2025, Pha Mor E Daeng and the checkpoint giving access to the temple ruins have been closed for extended stretches on safety grounds, with rangers and equipment pulled back from the immediate border area. Sections of the park further from the frontier have generally stayed open. Call the park office (0 4581 6000) or check current status before you drive out — this is not a park where you want to arrive on spec.

When conditions allow, the main path leads up to Pha Mor E Daeng, a cliff stretching around 300 metres and rising over 500 metres above the Cambodian plain below — one of the more dramatic viewpoints in northeast Thailand. A 1987 discovery revealed a set of bas-relief carvings cut into the rock near the cliff stairway, now estimated at roughly the 10th century — older than the temple above them. The forest itself is dry evergreen, mixed dipterocarp, and deciduous by turns, and wildlife — wild hogs, barking deer, gibbons, civets — moves across the unmarked border in both directions; sightings are a matter of luck rather than a managed encounter.

Insider Tip: Go for sunrise if the viewpoint is open. The cliff faces the plain below, and the “sea of mist” that settles over it from late rainy season into early winter is the single most-photographed sight here — arriving after 9am mostly means you’ve missed it.

Cool season, November to February, is the easier time to hike and gives the clearest long views; the hot season (March-May) turns the exposed cliff walk uncomfortable by mid-morning. Sturdy shoes, sun protection, and your own water are essential — there’s little shade on the approach. Two other Si Sa Ket Khmer sites worth pairing with a visit here: Sa Kamphaeng Yai Khmer Ruins and Prang Ku Khmer Ruins, both a similar era and both firmly on undisputed ground.

Getting here means your own car — there’s no scheduled public transport to Baan Phumisral. From Si Sa Ket town it’s roughly 98 km via Kantharalak; if you’re flying in, Ubon Ratchathani Airport is the nearest, about 100 km (1.5 hours) away, since Si Sa Ket has no airport of its own.