Wat Nakhon Kosa

Wat Nakhon Kosa is an ancient Buddhist temple ruin in Tha Hin Subdistrict, Mueang Lopburi District, Lopburi town, central Thailand. Located near the Lopburi River and Phra Prang Sam Yot, it features a large bell-shaped chedi, remains of a Khmer-style prang and vihara foundations. Originating in the Dvaravati period and later modified in the Khmer and Ayutthaya periods, it is notable for its layered architecture and archaeological importance within Lopburi's historic core.

Visitors can expect an open-air archaeological site in the historic centre of Lopburi with ruined brick and laterite structures set on flat ground. The main features are a large bell-shaped chedi on a high base, the remains of a Khmer-style prang, and foundation traces of a vihara and surrounding walls. The site is largely roofless and without active worship buildings, surrounded by modern town streets, and is explored on foot for viewing ancient stucco, laterite blocks and layered construction styles.

Wat Nakhon Kosa is an archaeological site with origins in the Dvaravati period (7th-9th century), later developed during the Khmer period in the 12th-13th century in Bayon style, and restored during the Ayutthaya period. The large bell-shaped chedi and prang remains demonstrate successive building phases. The site reflects Lopburi's role as an important Dvaravati and later Khmer-influenced centre before becoming a key Ayutthaya city.

The site is a historic Buddhist temple ruin representing the long continuity of Buddhism in central Thailand. Its layered Dvaravati, Khmer and Ayutthaya elements illustrate cultural and architectural transitions in Lopburi and it remains a protected ancient monument valued for education and heritage appreciation.