The south and western branches of Tre-Garnedd moat are the only remains of a medieval mansion on the edge of Malltraeth Marsh. It was once the seat of Gruffydd ap Rhys or Llwyd, who was knighted by 1301 and was the leading Welshman of north Wales through the earlier fourteenth century. There is a tradition of a seige in 1322.

This is a rectangular enclosure, roughly 70m north-south by 90m, defined on the south and west sides by a slight bank and a broad ditch or moat, 8.5-12m wide. The moat acts as a pond at its south-western angle. It is overlain by modern farm buildings. There were said to be visible traces of the house in the twentieth century.

Source: RCAHM Anglesey Inventory (1937), cxlvii, 90-1
NMR Site File

John Wiles 03.09.07