The farmstead at Blaen Gwnys is named on the 1833 1? to 1 mile Ordnance Survey map. On the 1840 parish tithe map of Merthyr Cynog, when it was owned by a Roger Watkins who also owned Tygwyn and Login to the west, and tenanted by a Morgan Pugh, it is shown with the layout still visible today. The farmhouse NPRN 242213 lies to the north of a yard aligned roughly northeast-southwest, with fold NPRN 242315 lying to the south. The yard is entered by a short holloway, approximately 50m long, from the northeast. The holloway leads to the fields above. On the 1st edition 25? to a mile Ordnance Survey map of 1891, the two buildings are shown in outline only, suggesting that they had fallen out of use at that time. When visited in April 2008, the farmhouse was a ruin, the walls less than 1m high.
J.J. Hall, Trysor, 25 April 2008