| Diffwys | |
| Elevation M: | 750 |
| Prominence M: | 148 |
| Range: | Rhinogydd |
| Listing: | sub Marilyn, Hewitt, Nuttall |
| Location: | Gwynedd, Wales |
| Map: | Wales Gwynedd |
| Coordinates: | 52.7915°N -3.9872°W |
| Grid Ref Uk: | SH661234 |
| Topo: | OS Landranger 124 |
| Fetchwikidata: | ALL |
Diffwys is a mountain in Snowdonia, Wales, near Barmouth and forms part of the Rhinogydd. On the north side is an exposure of the Caerdion Syncline. It is technically a subsidiary summit of Y Llethr, missing Marilyn status by 2m. It is therefore a sub Marilyn.
The summit has a trig point. To the north is Y Llethr and Crib-y-rhiw, to the east is Y Garn, to the south is Cadair Idris, and to the west is its top Diffwys West Top.[1]