Tyrrau Mawr or Craig-las is a subsidiary summit of Cadair Idris in the Snowdonia National Park, in Gwynedd, northwest Wales.

It lies to the west of Cyfrwy, and can be climbed by taking a west bearing from the Pony Path at Rhiw Gwredydd.

Below the crags lies Llyn Cregennen with its small island.

The reflection of Craig-las from this lake is one of the famous images associated with Snowdonia.

To the east of the summit lies the large ancient cairn, Carnedd Lwyd.