Wat Khao Phra Angkhan (‘angkhan’ is Tuesday in Thai with Phra Non as its image posture) is an extinct volcano mentioned in the legend That Phanom that in 535 BC, Buddha’s ashes were placed here. In 1977 Phra Panyawutthitho came to build a temple on the hilltop and moved the buddha’s ashes to store in the stupa in the top ubosot which was built in a unique style containing Thai arts of various periods. Surrounding the ubosot are ancient sema (boundary) stones from the Dvaravati period made of basalt which is found nowhere else in Thailand. One of the semas has bass reliefs of a person, stupa, lotus and a wheel of Dharma dating back to the 8th - 9th Century A.D. These prove that Buddhism has been practiced here since ancient times.
Khao Phra Angkhan is a wide based hill formed by a volcanic eruption in the Quaternary Period, approximately 700,000 years ago. From above its shape looks like a garuda spreading its wings with its head pointing to the south. The main rent is at Khao Kraduk (Khao Pa Cha), summit formed by fast cooling lava that vertically accumulated into the form of a plug dome. Around Khao Kraduk is a caldera or depression formed by a collapse of the vent. This is the earliest evidence of a caldera in Thailand. Wat Khao Phra Angkhan is situated on the edge of it.