Twyn Tal-y-cefn is a 702m hill in the Black Mountains marked by a cairn, although this is not according to the map the highest point – which is slightly further North.
The approach to this hill is on a well-maintained gravel path and ascends gently to the highest point – making this a very easy ridgeway walk.
The cairn and highest point are just off of the footpath on a fairly flat and featureless top. On the day I walked it there weren’t many views due to drizzle and fog.
An easy hill to tick off as it is directly on this circular route, probably has good views on a clear day. Might have to revisit at some point.