Wat Pi Rai was situated on the city island in the southwestern area of Ayutthaya at Pratu Chai sub-district. The temple was located on the crossing of Khlong Chakrai Yai (an extension of Khlong Tho) and Khlong Klaep. It was located on the west bank of Khlong Chakrai Yai and on the north bank of Khlong Klaep.
Wat Kao (no traces anymore) stood in the north, while Wat Pa Phat (no traces anymore) was in the south. Opposite Khlong Chakrai stood Wat Chana Man (no traces anymore).
The ancient site was cleared in the early 1970's during construction works of an expansion project of the (former) Ayutthaya Agriculture School (Withayalai Kasetrakam). There are no traces of foundations or brick work anymore at ground level and the temple is classified as disappeared. 
The site is mentioned on Phraya Boran Rachathanin's map drafted in 1926. Historical data about the monastery and its construction is unknown. The name of the monastery although is mentioned as Yi Rai.
A mid-19th century map indicates the location of Wat Pi Rai as Wat Salak or the "Monastery of the Chisel" and positions Wat Yi Rai just opposite of Wat Salak, on the south bank of Khlong Klaep. Seemingly through the years there has been a mix-up of the names of different sites in this area.
 Bangkok Post - 09 Dec 1972 - Work suspended on Ayutthaya sites. The article states that “machinery engaged on the Ayutthaya Agriculture School extensions ploughed up the ruins of at least five temples in the disputed area”. The work at the school was stopped after students had sent a petition to the NEC. The Director General of the Fine Arts Department at that time stated he was certain the damage had already been done.
Text by Tricky Vandenberg - October 2009 Text review & maps April 2011