The Bryn Gwyn stones stand about 280 metres (920 ft) to the south-west of Castell Bryn Gwyn, on the low ridge some 2 m (7 ft) above the valley of the Afon Braint on the Isle of Anglesey in Wales.

In 1723 Henry Rowlands described them as part of a ruinous circle of eight stones, some 16 m (52 ft) across.

An account of 1797 says that "ignorant country people supposing money was hid under them tore them up" and today only two stones, one slab and one pillar, stand in a modern field bank.

[5] A public footpath runs past the stones from Bryngwyn-mawr on the A4080 road, continuing north-east on a low ridge past Castell Bryn Gwyn and some 800 metres further to Caer Lêb.

[7] Further to the north-east at Tre'r Dryw Bach, another large stone circle was reported by 18th century visitors but has since been cleared away.