| Fan Bwlch Chwyth | |
| Elevation M: | 603 |
| Location: | Powys, Wales |
| Range: | Brecon Beacons |
| Coordinates: | 51.8825°N -3.5814°W |
| Grid Ref Uk: | SN912217 |
Fan Bwlch Chwyth is a peak in the Fforest Fawr section of the Brecon Beacons National Park and within the county of Powys.
Its summit (at 603 m) is marked by a trig point at OS grid ref SN 912217.[1]
The hill is formed from sandstones and mudstones of the Senni Beds Formation and Brownstones Formation of the Old Red Sandstone laid down during the Devonian period. A north-northwest - south-southeast trending fault runs across its north-eastern face.
This face is much the steepest and has its origins in the ice ages when a minor glacier grew at this spot. It has left a couple of arcuate moraines which are readily seen from the track. The glaciated rock face has been quarried. The quarry is designated as a site of special scientific interest for its geological interest.[2]
The entire hill is open country across which the walker can wander at will. A bridleway runs south-eastward from the minor road between Heol Senni and the A4067 road. The bridleway follows, in part at least, the vehicular track (no public vehicular access) to the disused quarry.