Lord Hereford's Knob (Twmpa) trail running loop
Lord Hereford's Knob (Twmpa) trail running loop
2
runners
Lord Hereford's Knob (Twmpa) trail running loop
02:11
17.0km
530m
Running
Embark on a difficult jogging adventure with the Lord Hereford's Knob (Twmpa) trail running loop. This challenging route covers 10.6 miles (17.0 km) and features a substantial elevation gain of 1727 feet (526 metres), typically requiring about 2 hours and 10 minutes to complete. You will experience running through heather-covered moorland, often sharing the path with wild ponies. The highlight is reaching the summit of Twmpa, also known as Lord Hereford's Knob, where you are rewarded with expansive views across the Welsh and English countryside, including the distant peaks of the Brecon Beacons and Pen-Y-Fan.
When planning your visit, be aware that the trail includes a steep, grassy ascent to Twmpa's summit, which is the most strenuous part of the journey. You should prepare for sections that can be quite boggy, especially the descent from Twmpa and areas leading to a country road, particularly after rain. Wearing proper footwear with excellent grip is essential for navigating the natural, sometimes muddy or steep ground. This route is best enjoyed when conditions are drier to avoid the boggier sections.
This trail offers a rewarding experience within the Bannau Brycheiniog (Brecon Beacons) National Park, known for its rugged beauty. The route provides a unique opportunity to immerse yourself in the natural landscape, observing the local wildlife and geological features of the region. It stands out for its panoramic vistas and the distinct character of its moorland environment, making it a memorable choice for experienced trail runners seeking a demanding outing.
Last updated: April 23, 2026
Tips
Your route passes through protected areas
Please check local regulations for:
Waypoints
Start point
Parking
Get Directions
1.19 km
Twmpa (Lord Hereford’s Knob)
Highlight • Viewpoint
Tip by
3.47 km
Rhos Dirion summit
Highlight • Natural Monument
Tip by
8.40 km
Grwyne Fawr Reservoir
Highlight • Historical Site
Gwyne Fawr Reservoir -is located in the valley of the river Grwyne Fawr in the Brecon Beacons National Park, Wales. Completed in 1928, it has the capacity to hold 400,000,000 imperial gallons of water... There were Serious water shortages in most parts of the historic county of Monmouthshire. In fact By the end of the 19th-century, The area had seen a massive population increase as a result of the steel and coal industries but the supply of water to the area was complicated due to its high altitude. A site for a New Reservoir was chosen at the head of the Grwyne Fawr Valley mainly because at the height of, 1,725 ft / 526m above sea level making it the perfect plan with it being high enough to allow all of the Reservoirs water to be freely gravity fed to Abertillery and the surrounding areas. Work started 1912, but immediately hit numerous problems.
The road up the valley could not take the weight of the heavy traction engines used for haulage. So It was decided that a new railway would be required. Then hit the first world war and proceedings were put on hold. Work recommenced 1919, the railway was completed, connected to the main line at Llanvihangel Crucorney. A village of construction workers and their families grew in the valley at Blaen-y-cwm. A community of some 300 people lived there with a hostel, canteen, day school, police station and hospital. Workmen quarried 200,000 tons of sandstone for the construction of the dam. Large boulders weighing up to 5 tons each were set in concrete to form the dam, which is 130 feet thick at its base, the walls were then faced with dressed stone. A 16-inch diameter steel pipeline was tunnelled through Coity Mountain carrying water to a holding reservoir in Cwmtillery.
The dam was finally completed in February 1928, after which the railway and structures that served its construction were quickly dismantled including the workers village. The total cost of construction was reported to be £1 million.
Tip by
17.0 km
End point
Parking
Way Types & Surfaces
Way Types
7.13 km
4.70 km
2.46 km
1.72 km
856 m
135 m
Surfaces
8.99 km
4.37 km
2.36 km
810 m
333 m
135 m
Sign up to see more specific route details
Sign up for free
Elevation
Highest point (710 m)
Lowest point (320 m)
Sign up to see more specific route details
Sign up for free
Weather
Powered by Foreca
Sunday 12 July
26°C
9°C
0 %
Additional weather tips
Max wind speed: 25.0 km/h
to get more detailed weather forecasts along your route
This route was planned by komoot.
Frequently Asked Questions
Where is the best place to park for the Lord Hereford's Knob (Twmpa) trail running loop?
The trail is easily accessible from the Hay Bluff car park or Gospel Pass, both of which are common starting points for routes in this area of Bannau Brycheiniog (Brecon Beacons) National Park.
What is the terrain like on this trail running loop?
The trail primarily consists of natural, well-worn pathways, suitable for trail running. You'll encounter heather-covered moorland and rocky outcrops. Be prepared for a fairly steep and grassy ascent to the summit of Twmpa (Lord Hereford’s Knob). Some sections, especially the descent from Twmpa and parts leading to a country road, can be boggy, particularly in damp conditions. Proper footwear with good grip is essential.
What is the best time of year to run the Twmpa trail?
The trail offers stunning views year-round, but the best time for trail running is typically from late spring to early autumn. During these months, conditions are generally drier, reducing the likelihood of boggy sections. Winter conditions, including strong winds and potential snow, can significantly increase the difficulty due to the exposed nature of the hills.
Are there any permits or entrance fees required for this trail in Bannau Brycheiniog (Brecon Beacons) National Park?
No, there are no specific permits or entrance fees required to access the Lord Hereford's Knob (Twmpa) trail running loop within Bannau Brycheiniog (Brecon Beacons) National Park. However, standard national park regulations apply, such as keeping dogs on a lead and following the Countryside Code.
Is the Lord Hereford's Knob (Twmpa) trail running loop dog-friendly?
Yes, the trail is dog-friendly. However, as you'll be running through open moorland where wild ponies and livestock graze, it's crucial to keep your dog under close control, preferably on a lead, to protect the animals and comply with local regulations.
What notable landmarks or viewpoints can I expect to see along the route?
The trail offers breathtaking panoramic views. From the summit of Twmpa (Lord Hereford’s Knob), you can see across the Welsh and English countryside, including distant peaks like Pen-Y-Fan. You'll also pass near Rhos Dirion summit and the Grwyne Fawr Reservoir. Wild ponies are a common sight on the grassy slopes, adding to the scenic charm.
Are there any specific sections of the Twmpa trail that are particularly challenging or require extra caution?
The initial ascent to the summit of Lord Hereford's Knob is generally considered the most strenuous part, being quite steep and grassy. After this, the path can be 'easier on the knees' before another climb towards Hay Bluff. Be aware that some sections, particularly descents and parts leading to country roads, can become very boggy in wet weather. The exposed nature of the hills also means you should be prepared for strong winds and rapidly changing weather conditions.
Does this trail intersect with any other well-known paths?
Yes, the route incorporates sections of several other paths. You will find yourself on parts of the Cambrian Way, EuroVelo 2 - Capitals Route - part United Kingdom 2, and National Cycle Network Route 42 during this loop.
What kind of gear should I bring for trail running on this loop?
Given the varied terrain and potential for boggy sections, proper trail running shoes with good grip are essential. Due to the exposed nature of the hills, even on a clear day, it's wise to carry layers of clothing, waterproofs, and a hat. Navigation tools (like the komoot app) are recommended, especially in poor visibility, as well as sufficient water and snacks.
Is this trail suitable for beginner trail runners?
While generally rated as 'difficult' for jogging, the loop presents a good challenge for those with average physical fitness. The initial steep climb up Lord Hereford's Knob is the most strenuous part. If you're a beginner, be prepared for significant ascents and potentially boggy, uneven terrain. It's a rewarding route, but perhaps not ideal for your very first trail run unless you're confident in your fitness.
Comments
Want to know more?
Sign up for a free komoot account to join the conversation.
Sign up for free