Wat Pa Nai, or the Monastery of the Inner Grove, was located in the Pho Sam Ton Sub-district of Bang Pahan in Ayutthaya Province. The temple was situated north of the former Burmese Pho Sam Ton Camp, on the east bank of the old Lopburi River (1), on a stretch called Khlong Muang (Khlong Pho Sam Ton) today.

In situ is just fallow land covered in dense vegetation. Locals in the vicinity said the area was levelled.

The historical background and period of construction of the former monastery are not known.

Wat Pa Nai was in geographical coordinates: 14° 24' 46.29" N, 100° 32' 51.59" E.


(1) The old Lopburi River entered the Bangkok lowland in the Bang Pahan District. The waterway meandered in front of Wat Khao Din (Wat Wara Nayok Rangsan) in Pho Sam Ton Sub-district towards Wat Muang, passing Wat Pa Fai, likely located on its right bank. The area here was altered mainly by the construction of the Asian Highway in the second part of the 20th century, which cut through it. Near Wat Muang, we can find the remnants of the old river bed again. The waterway ran between Thung Ban Lao and Thung Pho Sam Ton towards Wat Tha Yak, near the northern royal tax station (both defunct). The stretch between Wat Muang and Wat Dao Khanong includes numerous old temple sites. Stretches of the old river can be seen left and right of the Wat Muang Canal, but much of the landscape has been altered due to landfilling. The old Lopburi River was, until the early years of the 20th century, an important and heavily used waterway. The river connected the northern area of Ayutthaya with the Hua Ro Market on the northeastern corner of Ayutthaya City Island. The waterway between Wat Muang and the Hua Ro Market, sometimes called the Pho Sam Ton River, consists of three connected canals: Khlong Wat Muang, Khlong Bang Khuat and Khlong Hua Ro.