TREHILYN. The mill was located by the stream, which was about one hundred yards from the main farm buildings. The water was taken from the stream with its source at Rhos-y-caerau. The mill building is still to be seen, also the mill pond, which was used to boost power during drought periods. The mill itself was free standing; the stones used were three feet in diameter and were driven by belt and pulley. In addition it had a thrashing machine driven by a shaft, and a gorse mill. The mill worked up to the late 1930s.
(Source: The Water-wheels of St Nicholas, Stephen Harries, in Melin (Journal of the Welsh Mills Society) 2 (1986), p.2.)
The mill is shown but not annotated on Ordnance Survey maps.
B.A.Malaws, RCAHMW, 24 June 2005.