Steeps › The steepest roads in Wales
The steepest roads in Wales
Wales is home to the street that briefly took the world record in 2019. Here is what is documented about it and its neighbour in the Conwy Valley.
Ffordd Pen Llech, Harlech
This public road in Harlech, in Snowdonia National Park, is about 0.2 miles (0.32 km) long. It is one of two roads that encircle Harlech Castle, a World Heritage Site, and it links the upper town with Harlech railway station on the Cambrian Line. The name comes from the Welsh pen and llech, often rendered as "end of the rock" or "stony headland".
Wikipedia gives the steepest section a tangent gradient of 1:2.73, about 36.6%. UK practice rounds this for road signs, so the warning at the top shows 40%. BikeRadar lists the street as 335 metres long with an average of 20% and a maximum of 28.6%, the centreline figure used by Guinness World Records after 2020. The 28.6% figure is for a 10-metre stretch.
Countryfile links the street with the Harlech Hell Hill climb, a cycling event. Read the full controversy on the 2019 Guinness record page.
Afon Ddu, Conwy Valley
BikeRadar lists Afon Ddu as 691 metres long with an average gradient of 22% and a maximum of 34.5%. It is a lesser-known climb than Harlech, and we did not find further background in the sources we opened, so we leave the description there rather than guess.
Visiting Harlech
Harlech Castle and the station are on the same hill, so you can see the road from the station. Take care on foot: the road is steep, and the descent is harder on your knees than the climb. Cars use it as an ordinary road, so keep to the side and watch for traffic. Check opening times of the castle and any local attractions before you travel.
Getting there
Harlech has its own railway station, at the foot of the road, on the Cambrian Coast line, served by Transport for Wales.
More
For comparison with English roads, see England, or the whole ranking.
The record, in short
Guinness named Ffordd Pen Llech the world's steepest street from 15 July 2019, then reinstated Baldwin Street, Dunedin, on 8 April 2020 after changing how gradient is measured. The Welsh street measured 28.6% on the new centreline method against 34.8% for Baldwin Street. It remains one of the steepest streets in the UK, and a sign at the top warns of 40%.
Why Harlech is steep
The castle stands on a rock above the sea, and the roads that encircle it have to climb that rock. The road links the upper town with housing and campsites near sea level, so people do use it every day. If you walk it, take the pavement and expect the descent to be harder on your legs. Harlech Castle is a World Heritage Site; check opening times before you travel.
Other Welsh steep roads
Afon Ddu is the only other Welsh road in our sources. Wales has many steep lanes in the mountains and valleys, but we only list those with a documented gradient. If you know of one with a published survey, tell us.
Frequently asked questions
Where is the steepest street in Wales?
Ffordd Pen Llech in Harlech, Gwynedd, is usually named, with a maximum of 28.6% by Guinness measurement.
How long is Ffordd Pen Llech?
About 0.2 miles (0.32 km).
Why does the sign say 40%?
UK practice rounds the 36.6% tangent gradient up for road signs, according to Wikipedia.