St Thomas's church is located to the south-east of the village of Groeslon, down a track close to Cefn Nen. It was built to designs of Henry Kennedy, architect, of Bangor in the period 1846-53. However, it has since been demolished and only its plan outline survives within the graveyard. Air photos of its plan suggests a nave with narrower chancel, vestry on the north lateral wall, porch on the south wall.
No further information.

David Leighton, RCAHMW, 18 November 2014