Wat Phra That Si Mongkhon (วัดพระธาตุศรีมงคล) is an important Thai temple located in the village of Ban That in the Waritchaphum district of Sakon Nakhon, which is around 1 hour northwest of Amphur Muang.
Wat Phra That Si Mongkhon features a Laotian style pagoda similar in style to the famous and brighter one at Wat Phra That Phanom. While Phra That Si Mongkhon does not house a body relic of the Buddha (like Phra That Phanom), it does house sacred gold and bronze Buddha relics which were uncovered around 1900 when the densely forested woods of the area were being cut down for farmland. It's believed the relics trace back to the 16th century, when the area was under the control of the great Lao leader King Setthathirath (ไชยเชษฐาธิราช).
It was believed that the Buddha relics should not be moved and that a temple and new village should be built in the area. So, in 1902 the first Wat Phra That Si Mongkhon was established. This temple underwent development and restoration over the years, until finally in 1983 the current tiered pagoda was completed to house the relics, and King Bhumibol the Great visited to formally consecrate the temple.
The base of Phra That Si Mongkhon is decorated with terracotta bas-relief depictions of the Buddha's life, along with several Buddha statues in different standing postures. The upper level of the pagoda includes additional Buddha statues in different sitting postures, leading up to the final spire.
The oldest building at the temple is a white walled shrine built in 1947, which is decorated in traditional Isaan folk style but with one unusual figure: a bas relief depiction of the Chinese god Yangu, who appears holding the Yin and Yang symbol in the gable of the building. It is highly unusual to see this ancient Chinese figure at a temple in Northeastern Thailand, the mythological figures being almost exclusively of Buddhist or Hindu origin. Inside the shrine is an old statue of the Buddha with a 9-headed Naga statue in the front.
Wat Phra That Si Mongkhon has a large congregation hall (Viharn), which contains the temple's main Buddha image. Here is where you can make merit and ask for a blessing, placing a donation in the slot of the sturdy box which looks like a safe. You'll also find a colorful statue of the Buddha under the temple's Bhodi tree.