Wat Tha Pho, or the Monastery of the Landing of the Bodhi Tree, was situated on Ayutthaya's city island in the south-eastern area of the city in the Pratu Chai Sub-district.
Wat Tha Ma stood on the east bank of Khlong Makham Riang (1), between the Makham Riang Canal and the canal leading to Wat Suwandararam (2). Wat Kamphaeng was northeast, Wat Suwandararam east, Pom Phet south and Wat Tha Ma northwest.
Historical data about the monastery and its construction are not known.
Wat Tha Pho on the maps:
I believe the temple shows on Kaempfer’s sketch and draft map. Engelbert Kaempfer was a medical doctor working for the Dutch VOC (Verenigde Oost-Indische Compagnie) who surveyed the city of Ayutthaya in June 1690 CE. In this sketch, we find a temple on the east bank of Khlong Makham Riang, north of Pom Phet and near a bridge. The draft map confirms two temples opposite each other near a bridge over Khlong Makham Riang.
The monastery is also indicated on a 19th-century map drafted by an unknown surveyor. Wat Tha Pho stood on the west bank of Khlong Makham Riang, between the Makham Riang Canal and the canal leading to Wat Suwandararam. It was west of Wat Suwan and south of Wat Kamphaeng. Wat Tha Phai was southwest, Wat Trae northwest, both situated opposite the canal. The map displays the existence of a chedi.
Phraya Boran Rachathanin's map of 1926 CE shows Wat Tha Pho in a nearly identical location as on the 19th-century map. Wat Kamphaeng stood north, Wat Suwan east, Pom Phet south and Wat Tha Ma west opposite the canal.
Based on a 2007 GIS Fine Arts Department map Wat Tha Pho was in approximative geographical coordinates: 14° 20' 53.46" N, 100° 34' 33.10"E.
I believe the last can be discussed. The Makham Riang Canal today has another exit compared to the Ayutthaya era, where the canal ended next to Pom Phet. Kaempfer indicates another structure on the west bank of Khlong Makham Riang near a bridge opposite Wat Tha Pho, as explained above.
Wat Tha Pho should have been located in geographical coordinates 14° 20' 53.09" N, 100° 34' 35.21" E. The location of Wat Tha Pho which the Fine Arts Department indicates, was likely an, until today, unnamed temple site.
Footnotes:
(1) Khlong Makham Riang, or the Canal of the aligned Tamarind Trees, was before called Khlong Nai Kai. It is a still existent canal situated east on Ayutthaya's city island. The canal was a shortcut in the oxbow of the old Lopburi River. It has today its origin at Khlong Ho Ratana Chai below Wat Senasanaram and the Front Palace, and its mouth at the present Chao Phraya River, west of Phet Fortress. At the mouth was one of the eleven water gates of Ayutthaya called Pratu Nai Kai. The southern exit, which has today a water regulator, has been altered. The original mouth of the canal was about 170 metres more south, close to Pom Phet. Khlong Makham Riang is one of the three large canals running north to south, of which two still are in existence.
(2) Khlong Suwandararam is a canal splitting from Khlong Makham Riang towards Wat Thong (Wat Suwandararam) and called Khlong Nai Kai on PBR's map of 1926 CE. In the reign of King Phra Phuttha Yotfa (Rama I / 1782 - 1809 CE), the canal, which was situated on the west side of Wat Suwandararam and had a connection with Khlong Makham Riang and the Nai Kai Gate giving out on the old Lopburi River, was extended. The extension ran north of the temple in the eastern direction and joined the Front City Canal just opposite the mouth of Khlong Khao San. In this way, the monastery had more straightforward access via the water. A 19th-century map shows Wat Suwan surrounded by water. On PBR's map, the waterway on the south side seems to have been filled up.
