Prasat Preah Vihear (ព្រះវិហារ) is a Khmer (Cambodian) temple stunningly situated atop a 525-metre cliff in the Dângrêk Mountains in Cambodia, right across the border of Si Saket and Kantharalak in northeastern Thailand. It is also the name of the surrounding province.
Preah Vihear is perched on a hilltop with a commanding view of its surroundings. Predating Angkor Wat by 100 years, the history of the temple/fortress is somewhat unclear, but it is known to be dedicated to the god Shiva and thought to have been constructed in the reign of Suryavarman I (1002-50), with further significant additions by Suryavarman II (1113-50). Unlike most Khmer temples, the temple is constructed on a long north-south axis, instead of the usual rectangular plan facing east.
Though easily accessible from present-day Thailand, and for some years occupied by that country, the temple was nonetheless claimed by Cambodia on the basis of a map prepared during French colonial times. In 1959 Cambodia brought the dispute to the International Court of Justice, which in 1962 ruled that, because Thailand had for years accepted this map, Cambodia had sovereignty over Preah Vihear. Soon afterwards Cambodia was plunged into civil war. The temple remained open to the public from Thailand (although unreachable from Cambodia) until 1975, when it was occupied by the Khmer Rouge, whose rusting artillery guns still litter the area. It re-opened from the Thai side in 1998, and in 2003 Cambodia completed the construction of a long-awaited access road allowing Cambodians to visit the temple. In 2008, after a contentious nomination process, the temple was listed as a UNESCO World Heritage Site.
As of May 2014, citizens of Thailand are denied access from Cambodia, no exceptions. Some Khmer-speaking Thais have been known to sneak in with a group of Khmer visitors.
The nearest significant Thai town is Ubon Ratchathani. The temple is at the end of Route 221, but public transport options are limited and the easiest option is to charter a car for the day (1000 baht and up, plus gas). The roads are surprisingly good and, depending on how hard your driver hits the gas pedal and/or how many water buffaloes decide to cross the road along the way, you can get there from Ubon in an hour and a half.
If this is out of your budget, the nearest town of any size is Kantharalak, which can be accessed by frequent public bus in 2 hours or so from the nearby towns of Ubon Ratchathani and Si Saket. For the last leg of the trip (34 km), however, you will have to hitchhike or charter a songthaew/tuk-tuk/moto taxi.
At the entry gate into Khao Phra Wiharn National Park, you will have to pay a 200 baht entry fee (Thais 20 baht); note that the park is open only from 08:00 to 15:30. The road ends at a large parking lot, the final leg (less than a kilometre) into Cambodian territory you will have to cover on foot. At the Thai immigration post you'll be charged an additional 5 baht for a second ticket, and you'll also have to show your passport - they'll take a photocopy, but no stamps are issued and no visas are needed. After the road ends, walk over the smooth rock surface to the entry gate and pay another 200 baht fee (this one to enter Cambodia) and get your ticket punched, and now you can proceed to the ruins.
How to get there: From Bangkok, use Hwy 1 (Pahol Yothin Rd) turn right at Saraburi into Hwy 2 (Mitraphap Rd). At Amphoe Si Khew, turn right into Hwy 24, and travel via Amphoe Pak Thongchai, Sangka, and Ku Khan. Turn right into Hwy 221, and head to Amphoe Kantaralak and keep going to the park.
From Ubon Ratchathani, use Hwy 2178 and 221 via Amphoe Varin Chamrap, Samrong, Benjalak, and Kantaralak to the park.
The road from Siem Reap to the base of Prasat Preah Vihear via Anlong Veng, a distance of about 210 km, is now fully paved. A 4x4 or moto will be required to scale the steep road going up the hill, which you can arrange at the ticket office near the base of the hill; a 4x4 costs $25 roundtrip and a moto $5 roundtrip.
There is no public bus from Anlong Veng to Preah Vihear. A private car needs to be negotiated for about $50 although the starting price may be over $100 so bargain hard.
You can also reach the place on a three day motorbike trip from Kompong Thom. The highway between is completely sealed and in great condition (April. 2013).
Cambodian soldiers have established defensive positions near Preah Vihear, though they welcome tourists. Soldiers no longer seem to expect gifts and are quite hospitable when you are on the ancient staircase (eastern) side. Although there's no entrance fee, you do need to stop by the ticket office at the base of hill and get a ticket, which will be checked on the way up and at the temple. The ticket office also arranges transport by pickup truck ($25 roundtrip) and moto ($5 roundtrip). A new road for the first 3 kilometers has reasonable grades, but the last 2 kilometers are on the old road and have extremely steep sections.
The "Ancient Pathway" on the east side of the temple is now open to visitors; it's a pleasant descent with more than 2,000 steps through the forest; a modern wooden staircase parallels the largely ruined stone staircase, though two sections of old path are used. (Jan. 2013) The base of the staircase (which is more preserved) can also be accessed via a well signposted graded dirt road to the east of the ticket office.
The only way to get around is on foot. The 500 m elevation and the resulting breeze provide some relief, but it's still a hot and sticky 120 m (vertical) up the hill.
From the Cambodian side, you can hire a motorbike-taxi to take you up the steep ascent to the foot of the temple, but you'll still have to climb up the stairs yourself.
The Thai and Cambodian paths join together at the bottom of the slope (lower end of the adjacent map), and from here the only way is up.
There are several other minor sights in the area, accessible only from the Thai side:
There are ramshackle assemblages of shacks at both the Thai parking lot and the Cambodian base of the hill, as well as all the way along the path up the hill in the temple area itself. These sell not only the expected T-shirts, postcards and cans of Pepsi, but premium cognac and cigarettes by the carton as well: it's tax-free shopping for the Thais! As foreign visitors are few, expected to be besieged by little boys and girls shouting "Hello" and hawking postcards, but they usually take the hint after a couple of "bye-byes".
Places to eat are rarer on the ground than drink stalls, although there are some pretty basic grill stalls towards the end of the Thai parking lot shopping shacks.
For more selection and a semblance of hygiene, there are a number of roadside restaurants on the Thai side before the park entrance, along the road from Kantharalak.
Drink stalls are ubiquitous along the trail.
There are only very basic accommodation options in the immediate vicinity.
Cambodia: the village at the foot of the mountain provides two or three very basic "guesthouses" in simple wooden shacks. There is also a wooden, very basic guest house (shower and toilet outside) at the bottom of the steps, where the locals live. Shower is from a barrel of rain water and a bucket. Very, very basic but very clean. Electricity from 18:00 to 22:00.
Better to stay in Sra Em, 23 kilometers to the south, with five guesthouses in a row on the Anglong Veng side of town; some of these have restaurants. The guest house at the bottom of the steps mentioned above may not exist anymore. (Jan. 2013)
Thailand: the nearest place with a variety of accommodation is the town of Kantharalak (approx. 30 km), which is also the nearest place with direct bus services to Bangkok, Si Saket, Ubon Ratchathani, etc.
More distant Thai-side possibilities are the towns of Si Saket (approx. 95 km, and nearest train station), and Khu Khan (approx. 95 km, and most convenient place to stay near the border if travelling to/from Anlong Veng); and the city of Ubon Ratchathani (approx 120 km) - however, the most direct access to all these places is via Kantharalak.
If you have your own equipment, there is a campground in the Khao Phra Wiharn National Park. Call the Department of National Park, Wildlife, and Plant Life  at +66-2-562-0760.
Preah Vihear is the subject of a long-running territorial dispute between Thailand and Cambodia, and several soldiers on both sides were killed in clashes in 2008, 2009 & 2011. Both sides are trying to work out a diplomatic solution.
Land mines remain a real danger in the area, although the temple itself and the access paths have been painstakingly cleared by the HALO Trust. Stay on the beaten path, don't venture into any vegetation which has not been cleared recently, and heed the red warning signs, painted rocks and strings marking the limits of the demined area.
The cliffs are steep and no provisions are made to protect you from your own carelessness. Keep a very close eye on children.
The provincial government can be reached at tel. +66 64 393 940.