An underground power cable project in Phitsanulok province has uncovered the foundations of an ancient city wall believed to be more than 500 years old. Unearthed along Maha Thammaracha Road, the remains are believed to be the southern section of the city's historic defensive wall, possibly dating to the reign of King Borommatrailokkanat during the Ayutthaya period.

Archaeologists believe the structure dates to a period when Phitsanulok served as a major royal and military center. King Borommatrailokkanat resided in the city for approximately 25 years while conducting military campaigns against the Lanna Kingdom.

Historical accounts indicate that the Sukhothai-era earthen defenses of Phitsanulok were later replaced with brick walls. Much of the structure disappeared after partial demolition in the early Rattanakosin period and later urban development. A surviving section of the ancient wall remains visible at Wat Pho Yan.

The municipality has temporarily suspended excavation at the site while officials consult with the Fine Arts Office and the Phitsanulok Area Treasury Office on conservation measures. One proposal is to display historical information on the road surface to mark the wall's location. Authorities hope to preserve the archaeological remains while allowing essential infrastructure improvements to proceed.