667 m
Tarren y Gesail is a mountain in Snowdonia, north Wales. It is one of the Marilyns of the Cadair Idris group. Lying to the south of Cadair Idris, it and its neighbour Tarrenhendre form the bulk of the Tarren subgroup. The Tarrens rise from the south shore of the Llyn Mwyngil and end at the Dyfi estuary.