The Bryn Gwyn stones are found in a field close to the A4080 road between the villages of Dwyran and Brynsiencyn, Anglesey, North Wales.
The Bronze Age stones are from the 2nd Millenium BC and consist of a 4m by 3m stone and a 3m by 3m stone set either side of a field gate. The stones are two of the largest standing stones in Wales, and indeed the thinner stone once formed the wall of a very small cottage. Small notches have been cut into the top of the taller thinner stone, presumably for the roof purlins.
With the collapse of trees in recent years (2008) the stones are visible from the A4080 opposite Bryn Gwyn Hall. They are accessible by a footpath alongside the hedgerow. The footpath continues on to the remains of Castell Bryn Gwyn [another ancient site] in an adjacent field. In the 18th Century more stones existed and were said to be part of what would have been the largest stone circle in Wales [although this has not been confirmed by aerial photography].
Acknowledgement : A guide to ancient and historic Wales. Gwynedd. by Frances Lynch. HMSO.