Grwyne Fawr Valley

What could be a better way to celebrate the great outdoors than a walk in the Black Mountains? Hopefully the sun will be shining and the ground will be dry enough for a picnic!

grwyne fawr map

Click the map for a high resolution print version

This month’s walk visits Grwyne Fawr Reservoir with its impressive dam. The main route is quite strenuous and will require sturdy footwear, however there is an easy alternative route if you don’t mind missing the view. The walk is 4.5 miles long.

To Get There:

Take the Old Hereford Road out of Abergavenny. At Pantygelli, turn right before the garage. Follow the narrow road for about 2 miles to Forest Coal Pit. At the crossroads, shortly after Forest Coal Pit, turn left and immediately bear right, following the sign for Grwyne Fawr reservoir (7 miles). The road travels up the valley and through Mynydd Du Forest. After about 5 miles you will reach Mynydd Du forestry commission car park on the right.

View Larger Map

Location of the car park



At the rear of the car park there is a footpath; follow this to the road and walk a short distance with the Grwyne Fawr river on your left. Follow the track marked with ‘No Vehicles’ signs which forks from the road to the right.


After about 200 metres the track forks again. The right hand fork leads up and through the woods, (route A) but may be closed due to logging activity. It was closed halfway up when I went and there was a sign attached to a tree at the bottom of the track saying so.

Route A

If the route is open, follow the track up the hill. Cross the logging road and pick up the footpath in the crook of the bend. Continue through the woods until you go through a gate at the boundary.

Route B & C

If the woods are closed, continue on the left hand track which follows the edge of the woods. After about 450 meters you will reach a gate and stile. At this point, for an easy walk (Route C), continue along the track to the dam. Otherwise for those with strong legs and footwear, go through and, almost immediately, turn right up the steep bank. Follow the boundary of the woods up the hill until you reach the gate mentioned in route A.


On the open hillside, continue in a Northerly direction diagonally up the hill. Although this is a public right-of-way, there is little path to speak of and the ground can be uneven, so watch your step. You are aiming for the ridge, a little to the left of the highest point. You should reach the ridge near a pile of stones.


The cairn on the ridge

The cairn on the ridge


Admire the view! The Vale of Ewyas and England beyond is to the North and Waun Fach is to the south. Head west along the ridgeway.


After about 1 km a (muddy) track forks off downhill to the left. Follow it down to the dam.


Go through the steel gate at the bottom of the hill and turn right onto the track that immediately passes through an iron gate.

The Grwyne Fawr dam was opened in 1928, although construction had started in 1912. A large workforce was required and the foundations of the buildings that housed up to a thousand workers can still be seen around the site. The young Princes, William and Harry, controversially abseiled down the dam without helmets in 1998.
At the dam you can cross over to the other side where there is a nice spot for a picnic; but be mindful of the steep drops nearby. There is no route from this side, so cross back when you’re ready to head back.


The route that I had planned took me back along the tarmac road that travels along the valley floor, beside the river. To get to the road I saw that there was a track on the OS map zigzagging its way down the north bank beside the dam, and indeed there was. At the bottom there was a gate and footbridge to take me to the other side. The buildings housing all the dam gubbins are gated off and, of course, one should not trespass near these. However, when I passed through the iron gate out on to the road, I discovered that the gate I had just come through was marked ‘no entry’. So, the access situation is a little unclear. If you don’t want to risk potentially trespassing, as I may have done, you can return along the track that leaves via the iron gate at the top of the dam (route C). Whichever route you take, it’s about 2 miles back to the car park.


Article by Pete Hill

6 Responses to “Grwyne Fawr Valley”

  1. Excellent went there today bank hol Monday raining had my wet weather gear on so no problem thourghly enjoyable cheers

  2. Thanks Rob – That’s great to hear! – Cheers – Pete

  3. I love your photos as I am not likely to be able to visit personally it is helpful to see them. My father lived in the village that was built for the workers which is probably where the picnic site is now. He was only 6 weeks old when they moved there but stayed for 7 years. A school and infirmary was built amongst other things. My Paternal grandfather was a crane driver and his brother a train driver. My maternal great grandfather also worked there along with several uncles. Romance blossomed weddings and babies followed and so it went on.

    Thank you Denise

  4. Hi Denise,
    I’m glad to hear that you enjoyed looking at the photos. – It’s fascinating to hear about actual people who worked there – it makes it easier to imagine what it must have been like. – How funny that so many of your relatives worked/lived at the site! Thanks for your comment.

  5. hi my father and is brother both worked on the dam in the twenties is brother fred was killed on the dam 1927 accident with over head crane was an inquest in abergaveney intend one day to read

  6. To Denise and admin,
    my Grandfather worked on the dam – and he married a local girl at Beaufort in 1921 and my father was born in Beaufort.
    I have just found the book – stone and steam in the black mountains – which should be a good read when I get it.
    I wonder if we can get into a light contact re the Village etc.
    If so please indicate you are OK with this.
    Many Thanks
    Ken Osborne

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