Bwlch yr Efengyl is a mountain pass at an elevation of 551m (1,807ft) above the sea level, located in southeast Wales, near the English-Welsh border. It’s one of the highest roads of the country.
Set high in the Black Mountains within the Brecon Beacons National Park, the road to the summit is totally paved. It’s a very narrow, mostly single-track road with a few passing places. Watch out for cars and motorbikes at blind bends when heading into the Black Mountains. Its name probably refers to it being the route to the medieval Llanthony Priory in the valley to the south; the abbey is no more but there is still a pub in the remaining buildings.
The pass is 12.55km (7.8 miles) long, running north-south from Hay-on-Wye to Capel-y-ffin. It’s a great climb, though it’s pretty tough. Starting from Hay on Wye, the ascent is 8 km long. Over this distance, the elevation gain is 398 meters. The average percentage is 5%. And starting from Capel y Ffin, the ascent is 4 km long. Over this distance, the elevation gain is 228 meters. The average percentage is 5.7 %.
To drive the road without stopping will take most people between 25 and 35 minutes. Visibility heading north from the priory isn't great until you near the summit.
Located in the southeastern region of the country, the pass is generally accessible throughout the year. However, during winter, the summit experiences significant snowfall, often rendering it impassable for multiple consecutive days. It is imperative to have snow chains when traveling in winter conditions.
The opening scene of the 1981 "American werewolf in London" was filmed at the top. The summit hosts a small parking lot. The views, both back down the valley to the south and into mid Wales are eye-wateringly beautiful.