Cefn Eglwysilan is a 382m hill high above Pontypridd with twin summits, one of which is crowned by a wireless transmission tower, the other a trig point. You can walk it from many directions, varying in difficulty depending on how low you start. I parked on a fairly nearby layby, giving me a 5.1m loop, with only 748ft of ascent in total.

Valley View
The route I walked was largely via wide and gentle gentle tracks, offering great South Wales Valley views. | Minolta MD 35-50 @ 35mm, f11.
Valley View
Looking North. | Minolta MD 35-70 @ 35mm, f8.

I skirted the Northern summit, which has the wireless station on it, and as you round the corner and start to head South you get views over Pontypridd below.

Pontypridd
Pontypridd. | Minolta MD 35-70 @ 35mm, f11.

I walked it in the evening and only saw one other person on the whole loop, and they were a cyclist.

Cefn Eglwysilan
Cefn Eglwysilan is up on the left, you follow this track down until it goes up left and diagonal to the top. | Minolta MD 35-70 @ 35mm, f8.
Cefn Eglwysilan
Cefn Eglwysilan, northern top. | Minolta MD 35-70 @ 70mm, f8.
Cefn Eglwysilan
Cefn Eglwysilan Trig point looking North. | Minolta MD 35-70 @ 35mm, f11.
Cefn Eglwysilan
Cefn Eglwysilan Trig point looking South, in the distance on the left you can see Garth Hill. | Minolta MD 35-70 @ 70mm, f11.
Golden Hour
You can complete the loop by taking the Rhymney Valley Ridgeway walk back. | Minolta MD 35-70 @ 35mm, f8.

The views from the trig point are really impressive and well worth the walk, the footpaths are broad and easy to follow and there is a good pub nearby – the Rose and Crown – that you could add to your walk.