Cefn yr Ogof is the highest point of the hill to the west of Gwrych Castle near Abergele and Llanddulas. It is 204 m high. The view from the top is one of the hidden delights of the North Wales coast with views towards the Clwydian Hills, Denbigh Moors, (Mynydd Hiraethog) Snowdonia, the Great Orme, Anglesey and the Dulas valley. The name refers to the caves located on the hill.
It has recently been promote to HuMP status, having a prominence of over 100 metres.
Link to Cefn y ogof, hosted by the Gwrych Castle website. Llanddulas Limestone and Gwrych Castle Wood is an SSSI including the hill.