Region: Cwmcarn and Twmbarlwm, Caerphilly, South Wales
Walk summary: This 7.6-mile anti-clockwise Twmbarlwm circular starts at Cwmcarn Visitor Centre, follows part of the Cafall Trail and climbs through the forest to the trig point and Iron Age hillfort. It then follows the Cambrian Way and briefly joins the Twrch Trail before returning on the Cafall Trail. It has 1,539ft of ascent and takes around 4½ hours.
| Distance | 7.6 miles / 12.2km |
|---|---|
| Ascent | 1,539ft / 469m |
| Time | Approximately 4½ hours |
| Difficulty | Moderate — a long, steep zig-zag climb followed by an easier and mostly level return |
| Route | Anti-clockwise circular walk |
| Start and finish | Cwmcarn Visitor Centre |
| Main landmark | Twmbarlwm trig point and Iron Age hillfort |
| Suitable for | Regular walkers, fit beginners, active children and capable dogs |
The Twmbarlwm circular walk from Cwmcarn combines woodland, open common, far-reaching views and one of South Wales’s most recognisable historic summits. The steep climb through the forest is the main physical challenge, but it is followed by a much easier return across the high ground and down through Cwmcarn Forest.
This is also an active mountain-biking area. Parts of the walk share or briefly cross the Cafall and Twrch trails, so listen carefully and look in both directions before stepping onto a bike trail. Riders may approach quickly downhill or be concentrating hard while climbing.
Watch my Twmbarlwm circular walk
Twmbarlwm parking, map and GPX
- Parking and start: Cwmcarn Visitor Centre
- Parking: Paid parking is available at the visitor centre.
- GPX: Download my Twmbarlwm circular walk GPX
- Route app: View the route on Outdooractive
- Facilities: The visitor centre has local information, toilets, a shop, café, extensive seating and a nearby play area.
The visitor centre makes this an excellent family base, but the complete 7.6-mile route still requires reasonable fitness. Download the GPX before setting out because the walk uses several named walking and mountain-bike trails, and the correct turnings are not always obvious from a written description alone.
Twmbarlwm circular walk route description
Begin in the lower parking area on the opposite side of the river from Cwmcarn Visitor Centre. Walk towards the far end of the car park with the visitor centre on your left, then enter the woodland beside Nant Carn.
Following the Cafall Trail through Cwmcarn Forest
Follow the Cafall Trail through the trees, initially with Nant Carn and the small lake on your left. The sheltered woodland is attractive, but it receives limited sunlight and can hold water for a long time after rain. Expect mud and slippery ground during wet periods.
Mountain bikes use this area extensively. Remain alert at trail crossings and on any shared sections, especially where trees, bends or changes in gradient restrict your view. Do not assume a quiet trail is empty simply because you cannot yet hear a rider.
The long climb towards Twmbarlwm
Turn away from the Cafall Trail and begin climbing towards Twmbarlwm. The ascent is long and steep, although the path zig-zags through the woodland and makes the gradient more manageable. This is the hardest physical section of the walk.
The route passes the play-area level, continues through gates and briefly uses a forest road before returning to dirt paths. As you gain height, the dense woodland eventually opens and Twmbarlwm becomes visible ahead.
Twmbarlwm trig point and hillfort
Pass through the gate and tackle the final short, steep approach. This well-worn ground can be slippery when wet. An information board introduces Twmbarlwm and the surrounding landscape before the stone path leads towards the trig point.
Reach the trig point first and then continue to the visible earthworks of the hillfort. The raised summit position provides wide views across South Wales, while the shape of the ramparts is easiest to appreciate by walking around rather than simply stopping at the trig point.
We stopped here for coffee and sandwiches and spent around half an hour taking in the views. Cows, sheep and wild horses may be present on the open ground, so give every animal space and keep dogs under close control.
The Cambrian Way across the open common
Leave the hillfort through the gate and continue across the open high ground on the Cambrian Way. The character of the walk changes here: the difficult ascent is behind you, and the next section is comparatively level and open.
Continue for roughly a mile before descending left towards the next parking area. The landscape is open and exposed compared with the forest, so mist, wind and rain can make navigation and conditions more demanding than they appeared at the visitor centre.
Twrch Trail and the return to Cwmcarn
The route briefly joins the Twrch Trail before reconnecting with the Cafall Trail for the return to Cwmcarn. This is another section where walkers must remain particularly aware of mountain bikes. Follow the GPX route and trail junctions carefully rather than wandering onto a dedicated biking line.
The final woodland miles are mostly easier than the outward climb, although mud and tired legs still require care. Return to the visitor centre, where the café, toilets, shop and seating make it an ideal place to finish.
Twmbarlwm walk practicalities
- Parking: Paid parking at Cwmcarn Visitor Centre. It can become busy during weekends, holidays and good weather.
- Difficulty: Moderate. The long, steep zig-zag ascent is the main challenge; the return is largely flatter and easier.
- Underfoot: Forest roads, muddy woodland trails, surfaced paths and open common. Wear sturdy footwear with reliable grip.
- Mountain bikes: Several trails are shared or crossed. Remain alert, keep children and dogs close, and never stand on a bike trail at a blind bend.
- Weather: Woodland can remain muddy after rain, while the hillfort and Cambrian Way are open to wind, rain and poor visibility.
- Livestock: Cows, sheep and wild horses may be encountered. Give them space and keep dogs on a lead when necessary.
- Beginners and children: Suitable for fit beginners and active children who can manage the distance and sustained climb.
- Facilities: The visitor centre has toilets, local information, a café, shop, seating and a nearby play area.
Preview the route in 3D
Watch the route before setting out to understand the forest climb, Twmbarlwm hillfort and high-level return.