One of several limekiln Groups (P39 to P47 in the notation of the survey) are situated on Carnau Gwynion, a series of limestone outcrops lying between the Nedd and Llia valleys. This group, P39 along with P40 & P41, lies within a roughly rectangular enclosure numbered 1508 on the OS. 1:2500 Map (1904). This was set aside as common land when the Great Forest Estate was sold by the Crown in 1830 and it contains three distinct limestone outcrops.

This group lies around the eastern outcrop of Carnau Gwynion, and is centred on SN92111456.
24 kilns were identified, in varying states of preservation. Although there are some well-preserved examples most are reduced to earthworks though even here structural details are frequently visible.