Route advanced between Tomen-y-mur (Nprn95476) & Pennal (Nprn300159) Roman forts (Margary RR69b).

Several segments of road are known south of Tomen-y-Mur (Nprn300006, 309188): the route past Trawsfynydd is uncertain (Nprn400872): there is an unconfirmed segment at Cefn-y-Clawydd - south of Dolgellau - (Nprn400836).

J.Wiles 21.10.03