A roughly 900m length of disused road or trackway, that pursues a rather irregular course north to south-south-east across Gelligaer Common from SO10150390 to SO10470307. It is described by CADW as having a central AGGER or raised cambered roadway, 4.0m wide and 0.5m high, with flanking ditches and counterscarp banks.
This is traditionally identified as a part of Roman road north of Gelligaer fort (RR621; NPRN 305956), although as described it bears only a superficial resemblance to such a work. Roman roads in Wales tend to be 6.0m wide and this road is possibly a more recent road. Engineered roads such as this appears to be only became commonplace from the eighteenth century.
The road was disused by the time of the OS County series 1st edition of 1877 (Glamorgan. XII.11), when the Roman attribution was already established.

Source: RCAHMW Glamorgan Inventory I.2 'Iron Age & Roman' (1976), 108-9
CADW Scheduling Report

David Leighton and John Wiles, RCAHMW, 16.05.2017