These mountains are located 30km northwards from Angkor Wat. There is a sacred hilltop site on top of the range and the area was declared a national park by the government of Cambodia.

Phnom Kulen is widely regarded as the birthplace of the ancient Khmer Empire and is located some 48km from Siem Reap. Of special religious meaning to Hindus and Buddhists, it was at Phnom Kulen that King Jayavarma II proclaimed independence from Java in 802 A.D.

The site is known for its carvings representing fertility and its waters which hold special significance to Hindus. Just 5cm under the water's surface over 1000 small carvings are etched into the sandstone riverbed. The waters are regarded as holy, given that Jayavarman II chose to bathe in the river, and had the river diverted so that the stone bed could be carved. Carvings include a stone representation of the Hindu god Vishnu laying on his serpent Ananta, with his wife Lakshmi at his feet. A lotus flower protrudes from his navel bearing the god Brahma. The river then ends with a waterfall and a pool.

The Khmer Rouge used the location as a final stronghold as their regime came to an end in 1979. Nearby is Preah Ang Thom, a 16th century Buddhist monastery notable for the giant reclining Buddha, the country's largest.