It was some 160 miles in length. Today some sections are modern highways, others still traceable as Roman though much degraded, and at various places there is much debate as to where the road ran.
In the north the route is believed to follow the western bank of the river Conwy from Canovium, a fort at Caerhun, passing through Trefriw, then leading on to Betws y Coed, with a branch leading to Caer Llugwy near Capel Curig. The route then passed through Dolwyddelan, running up Cwm Penanmen and past the higher parts of Cwm Penmachno. The route then leads on past Llan Ffestiniog to the Roman fort of Tomen y Mur, near Trawsfynydd before continuing south towards Dolgellau.
South of Dolgellau the route passes over Waen Llefenni into Cwm yr Hengae to Aberllefenni. Part of the narrow-gauge Corris Railway between Aberllefenni and Maespoeth Junction may run along the line of the Sarn, and the modern A487 trunk road between Corris and the Afon Dyfi may follow its route. It probably crossed the Dyfi by a ford or ferry near the Roman fort at Pennal.
In Ceredigion Sarn Helen runs as part of a B-road in Bronant, and six miles south there is a long stretch through the hamlet of Stag's Head. It passes down to Llanio where there was a small Roman fort named Bremia, and crosses over to Dolaucothi before reaching Llandovery. The route survives as a minor road here, although severely affected by potholes where it crosses the mountains.
A further section of Roman road leading north-eastwards from Neath (Roman 'NIDVM') to Banwen at the southern edge of the Brecon Beacons National Park is known as Sarn Helen. It continues north-eastwards through the Park to the north-west of Ystradfellte, beneath Fan Frynych and then across Mynydd Illtud en route to the Roman fort of Y Gaer, Brecon (Roman 'CICVCIVM').
The Sarn Helen Trail
The Sarn Helen Trail is a long-distance mountain bike route. Devised by Tim Woodcock in 1996, it runs for 270 miles from Conwy on the North Wales coast to Worms Head in the south. A book, detailing the route, was first published by MBRUK (Mountain Bike Routes UK) in 1998.
Sarn Helen Hill Race
The road gives its name to an annual hill race. Starting and ending at Lampeter, this 16.5-mile (26.6 km) multi-terrain race takes place in May each year. It claims to combine "the speed of road racing with the rigours of cross country and fell running over a challenging picturesque course" which includes sections of the Roman road. It has been held every year since 1980, organised by the Sarn Helen Running Club, with course records of 1.34.29 (Male, 1982) and 2.00.18 (Female, 1990).[not in citation given]
In popular culture
John Wilkinson, Sarn Helen (Cambridge: Equipage, 1997)
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