Post Gwyn is a subsidiary summit of Cadair Berwyn in north east Wales.

The range also includes the Hirnantau to the west, which are crowned by Cyrniau Nod.

The summit is the highest bump on the most westerly of Cadair Berwyn's long south ridges.

No well trodden paths have developed here and the summit is seldom visited.

The summit is marked by a pile of stones and offers views of Cwm Rhiwarth.