Wat Mahathat, Sankhaburi

Sankhaburi was formerly Mueang Phraek Si Racha, a moated town with Dvaravati and Khmer remains; some scholars link it to the state of Chen Li Fu in Chinese records, though this is debated. 'Phraek' appears in the Ramkhamhaeng inscription; sources disagree on when it was renamed Sankhaburi, so only 'the Ayutthaya period' is safe. Under King Intharacha (1409–1424) his son Chao Yi Phraya ruled it as a royal-son town; a statue of him stands in the temple. The ancient town as a whole is not registered, only its temples.

The Fine Arts Department says the founder and date are unknown and the style is early Ayutthaya. The site has a collapsed square-based main chedi, one prang with a lobed starfruit top, a row of seven octagonal chedis and a second row with the prang and two more, an ordination hall facing the river, a roofless nine-bay main vihara reduced to its pillars, and a cloister. Some travel sites say there are three prangs, but the department describes just one.

The image villagers revere here is Luang Pho Mo, also called Luang Pho Lak Mueang; Luang Pho Chai, often confused with it, is at Wat Phra Kaeo. King Rama V visited on 7 October 1901 on his trip north (date from a single source), and a pavilion was built in front of the temple to receive him. A 1959 photo shows the main chedi and cloister before restoration, and one travel source mentions a restoration in 1983.

In 2021 the Fine Arts Department noted the temple had no long-term management plan, so it drew up a three-year plan, completed a test excavation and began restoration and landscaping as of 2 March 2021. The temple now has two museums, the Luang Pho To and Luang Pho Phra Palat Chuang museums, with over 1,000 local antiquities, and a market on Buddhist holy days.

It is open about 08:30–17:00 and free, with parking. From Chai Nat take Highway 340 south to the Sankhaburi clock tower, then turn left for about 500 m. Don't climb or sit on the ruins, dress modestly, and expect little shade at midday. November–February is most pleasant, and the Noi riverside can flood in September–October. Wat Phra Kaeo, with its square chedi and Luang Pho Chai, is about 2 km away.