Wat U Taphao was situated in the Pho Sam Ton Sub-district of Bang Pahan in Ayutthaya Province.
The temple was located between Wat Sing and Wat Chedi Hak, on the east bank of the old Lopburi River, on a stretch called Khlong Ban Muang (Khlong Pho Sam Ton) today.
In situ is an earthen mound with some scattered broken old bricks. There were no traces of fragmented Buddha images nor sema stones seen when visiting the site.
In the vicinity of Wat Chedi Hak, we met a local who told us that all the bricks of this former temple had been gathered and transported by boat to Bangkok at the beginning of the 1950s. [1]
The historical background and period of construction of the former monastery are not known.
The temple bears the same name as the Dvaravati-era settlement Mueang U-Taphao in Nong Saeng (Saraburi Province). One of the possible translations of Taphao could be 'Chinese junk' (aka Samphao) U-Taphao could be roughly translated as the 'Cradle of Chinese Junks' and referring to a harbour.
Wat U Taphao was in geographical coordinates: 14° 25' 31.91" N, 100° 33' 4.00" E.
References:
[1] Interview with Khun Tawet on 11 January 2013 in the vicinity of Wat Chedi Hak.