Maen Llia is a massive slab of conglomerate stone located at the head of a pass between Fan Llia and Fan Nedd. It measures 3.61m high, 2.75m wide and 0.46m thick. Although it allegedly bears faint traces of a latin/ogam inscription (not recently confirmed), its geometric relationship with nearby Bronze Age monuments points to its prehistoric origins.
Survey revealed that Maen Llia has a precise geometrical relationship with a nearby round cairn (NPRN 84539), a concentric embanked earthwork (84544) and, between all three, a platform (84549).
David Leighton & David Percival, RCAHMW, November 1984.