A rectangular building of two, possibly three, compartments with attached enclosure(s) is located on the south side of Banc Llechwedd-ddu, close to the foot of Banc Lletty Ifan Hen.
The building (at NGR) was built on a platform cut into ground rising to the east to a depth of 0.75m and built out to about 0.3m high on the west. The building is defined by stony earthwork banks partly obscured by large stones and boulders dumped onto it during recent land improvements. It measures approximately 11.5m (E-W) by 3.5m wide internally. It is bounded at its east end by the platform `hood? and elsewhere by broad stony banks up to 1.5m wide and 0.6m high; the long north, uphill, side is flanked by a shallow ditch. The interior is grassed-over rubble. There is some suggestion of a subdivision just west of centre but no obvious entrance. At its west end, at a lower level against the foot of the platform terrace, is another slightly narrower compartment defined by slighter banks 0.6m wide and 0.3m high, and measuring overall 5m (E-W) by 3m. Amongst the rubble dumped on the site, some smaller boulders are possibly structural.
Adjacent on the south is a sub-rectangular enclosure measuring 24m (NW-SE) by 18m, bounded on the north partly by the building and partly by a stony bank 1m wide and 0.2m high, on the south by a stony bank 1.5m wide and 0.3m high edging boggy rush-grown ground, on the west by a stony bank 1.5m wide and 0.2m high, and on the east by a slightly embanked stony scarp slope up to 2m wide and 0.6m high.
There are faint traces of cultivation ridges within the enclosure aligned NE-SW. To the south of the enclosure, beyond the boggy stream course, cultivation ridges are also visible, immediately below the access track, in an area some 36m by 25m.
To the east side of the building and enclosure air photos indicate two conjoining rectangular enclosures defined by low grassy banks and only faintly visible on the ground. In total they measure some 40m (E-W) by 32m, subdivided into two roughly equal areas by a N-S bank incorporating an outcrop band cleary visibile on the ground. The entire area to the north and west of the site is one of extensive relict cultivation (see NPRN 418088).

David Leighton, RCAHMW, 7 December 2012