| Mynydd Ceiswyn | |
| Elevation M: | 605 |
| Elevation Ref: | [1] |
| Prominence M: | 27 |
| Language: | Welsh |
| Location: | Snowdonia, Wales |
| Range: | Cadair Idris |
| Coordinates: | 52.7089°N -3.8185°W |
| Grid Ref Uk: | SH 7724 1390 |
| Topo: | OS Explorer OL23 |
Mynydd Ceiswyn is a mountain in Wales. It is the peak south of Waun-oer in the Dyfi Hills. On the east side of the mountain is the valley of the Nant Ceiswyn, and Cwm Hengae lies to the south.
Two minor dip faults cross the mountain,[2] and the Ceiswyn Formation is named after this mountain.[3]