There are records of a deserted medieval village having been located on Mynnydd-y-Gaer, although the location is uncertain. A house platform has been identified on the east side of the hill. The only high-level road over the hill is a minor road that runs north-south over the saddle between Mynydd-y-Gaer and Foel Fynyddau, close by the house platform, and also past a number of disused coalmining levels, in the vicinity of Gelligaer Fach Farm, and probably dating at least to the 19th century.