Wat Pa Fai, or the Monastery of the Cotton Quarter, was located in the southern area of Ayutthaya’s city island in the Pratu Chai Sub-district. The former monastery was situated east of the Somdet Phra Sri Nakharin Park and the Chakrai Yai Canal (1). The site is part of the Ayutthaya Historical Park.
The temple stood south of Khlong Pa Mo and the present Phra Nakhon Sri Ayutthaya Correctional Institution, east of Wat Som and north of Wat Thong Pa Mo (which was located on the premises of the current Phra Nakhon Sri Ayutthaya Hospital).
The monastery shows on Phraya Boran Rachathanin's map drafted in 1926 CE. Wat Pa Fai stood here on the same east-west axis as Wat Som.
The 2007 CE GIS Fine Arts Department map indicates the temple north of the Suan Somdet Uthong Soi 4 based on what I presume is an excavation site and is, thus, slightly more north than on the PBR map.
No traces above ground level could be found, and as such, I classified the monastery as defunct.
Historical data about the monastery and its construction are not known.
Near Wat Pa Fai were two markets. A market on Iron Quarter Road selling sundries and metal goods, knives, and machetes and another fresh market called the Head of Road Market. In front of the monastery, there were shops selling books of white and black paper. [1]
Wat Pa Fai was in geographical coordinates: 14° 20' 46.99" N, 100° 33' 30.41" E.
Footnotes:
(1) Khlong Chakrai Yai is part of a waterway running through the west of Ayutthaya from north to south. The canal was the extension of Khlong Pak Tho and ran from the Lam Hoei Bridge to the Chakrai Yai Gate opposite Wat Phutthaisawan. The canal was a shortcut through the oxbow of the Lopburi River and connected the old Lopburi River, present Khlong Mueang in the north with - what is today - the Chao Phraya River in the south. Ban Chakrai was a village located on the city island but outside the city walls. (2) Khlong Pa Mo, or the Pot Quarter Canal, is a defunct canal. It was an eastward extension of Khlong Tha Phra and started at the latter's confluence with Khlong Chakrai Yai. Beyond this confluence, it continued in an eastern direction as Khlong Pa Mo and joined the Pratu Thep Mi Canal. There is evidence that this canal continued eastwards in a straight line to join Khlong Makham Riang. (3) The word "pa" (ป่า) is usually translated as "forest", but in the Ayutthaya era, it also indicated a place where specific products were made and/or sold. Chris Baker translates it as "a quarter". [1]