Roman road supposed to link Caernarfon (NPRN 93511) and Caer Gai (NPRN 95436), as described by Margary (RR68). Only the section between Tomen-y-Mur (NPRN 95476) and Caer Gai, can be verified.

There is no substantive evidence for a Roman road between Caernarfon & Tomen-y-Mur: the section of road, known for about 1.5km north-west of Tomen-y-Mur (NPRN 303423), cannot of itself be considered as a long-distance route.
Immediately south-east of Tomen-y-Mur are the remains of bridge (NPRN 89467), from where the road runs to the south-east (NPRN 89468, 89470 - uncertain section = 89480) & then generally east to Dolddinas (NPRN 89466, 400425, 89472) where there is a cluster of pratice works (NPRN 93764).
From Dolddinas a well preserved and dramatic section of road runs south-east to Llyn Hiraethlyn (NPRN 309160, 309123) and another cluster of practice works (NPRN 54524), before descending into the Prysor valley (NPRN 89704).
There are two possible routes south of the Prysor: (1) running generally east-south-east by Moel-yr-Wden & Bwlch-y-Bi into the Lliw valley (NPRN 309149, 309126, 309145, 309144); (2) running east to Moel-y-Slates & along the north of the Lliw valley (NPRN 400555, 401036).

The overall route was established by Irvine (1956), Margary (1957, 82-4) & Bowen & Gresham (1967, 255-6). Aerial reconnaissance has materially altered this route (Crew & Musson 1996 'Snowdonia from the Air', 30).

Sources: Irvine in the Bulletin of the Board of Celtic Studies17.2 (1956), 57-68
Margary 'Roman Roads in Britain' II (1957)
Bowen & Gresham 'The History of Merioneth I' (1967)

John Wiles 12.06.07