St Illtyd's Motte

St Illtyd's Motte, also known as St Illtyd Castle Mound, is the remains of a motte-and-bailey castle in the village of Llanhilleth, Blaenau Gwent, Wales. It was probably destroyed by Llywelyn the Great in the early thirteenth century and not rebuilt. The remnants are a Scheduled Ancient Monument.

The surviving motte is a roughly circular steep-sided, flat-topped mound about 36 m in diameter and 6.16 m high. It is surrounded by a partially filled-in ditch that is 4 - 5 m wide and 0.8 m deep.