A rabbit farm of the early nineteenth century is located on the south part of the steep ridge of Cefn Cul between 270m and 460m above OD, to the west of Cefn Cul farmhouse (nprn 408800), which is believed to have been the warrener's cottage.
The farm covers an area of 54ha and is enclosed by a stone wall. Three walled enclosures lie within it, at the northwest corner (SN 85221880), the northeast corner (SN 86001801) and at centre, the largest (SN 85631849), which contains two pits.
Within the main enclosure lie 43 pillow mounds and 12 pit traps. The pillow mounds are turf and heather grown banks, ditched on the uphill side, of wide variation in size: 12m to 86m long, 1.6m to 5.5m wide and 0.4m to 1.5m high. A system of drainage ditches and banks contemporary with the mounds lies amongst them.
Typical pillow mounds lie at:
SN 85271879, SN 85481879, SN 85811876, SN 85891871, SN 85821866, SN 85731864, SN 85921856, SN 85221851, SN 85721848, SN 85431838, SN 85401821, SN 85541817, SN 85381803

The traps (now mostly destroyed) are stone-lined bell-shaped pits between 1.5m and 3m in diameter and about 0.7m deep. An atypical trap, at SN 5391836, is of rectangular form. Also within the enclosure are the remains of a small building, at SN 85391836, and a small horse-shoe shaped structure at SN 85201866. At the south end of the enclosure, at SN 85421793, is a curving length of low bank, apparently the remains of an earlier enclosure cut through by the later wall.

Cefn Cul is the most compact of the three nineteenth century rabbit farms in the Brecon Beacons.

Surveyed at 1:2500, B.A.Malaws, RCAHMW, February 1988