Hidden above the small village of Tanygrisiau, this route weaves through the slate-scarred hillsides to reveal the sweeping curve of Stwlan Dam, the summit of Moelwyn Mawr, and the atmospheric ruins of Rhosydd Quarry. It’s a day walk that blends mountain challenge with history and light – perfect for photographers seeking texture, drama and a real sense of place.
This route offers two distinct experiences. The lower path provides a steady, scenic walk through slate country with views over Blaenau Ffestiniog, while the upper route to Moelwyn Mawr adds a real mountain challenge. Both routes showcase North Wales at its best — rugged, photogenic and steeped in history.
| Detail | Information |
|---|---|
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Route length |
6.4 miles (10.3 km) |
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Elevation gain |
447–670 m (1,446–2,200 ft) |
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Highest point |
Moelwyn Mawr – 770 m (2,526 ft) |
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Difficulty |
Moderate to challenging |
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Start Point |
Lakeside Café car park, Tanygrisiau (near Ffestiniog Railway Station) |
The route begins from the public car park beside the Lakeside Café in Tanygrisiau, just along from the Ffestiniog Railway Station. It’s a convenient starting point with good access to the lower quarry tracks and the road leading towards Stwlan Dam.
Please avoid parking on the narrow access lane or in private spaces near the houses — they’re used by local residents and farm traffic. The main car park is inexpensive, usually quiet outside peak summer months, and right next to the café (a great place to grab a coffee or use the facilities before you head up).
If the main car park is full, you can find additional parking near the entrance to the Ffestiniog Power Station, just a few minutes’ walk away — but always check signage before leaving your vehicle.
Public transport is an excellent alternative: regular trains stop at Blaenau Ffestiniog, where you can connect to the Ffestiniog Railway for a scenic trip down to Tanygrisiau. From there, it’s only a short walk to the route start.
The café is your last reliable toilet stop before the hills — there are no public facilities at Stwlan Dam or beyond.
From the Lakeside Café, follow the road that bears left uphill (not the one that doubles back on itself). Cross the railway line and continue until you reach a small fenced-off utility building. The main footpath begins just before this building on your left – follow it across the field to join the old quarry route that winds towards Stwlan Dam.
The first stage climbs along a series of broad grassy embankments, remnants of the old funicular system that once lowered slate wagons down the valley. There are three of these terraces, each easy to follow and offering progressively wider views across Tanygrisiau and Blaenau Ffestiniog.
You’ll eventually reach a small parking area beneath the dam wall. The path to the top isn’t shown correctly on OS Maps. To find it, walk beneath the stone archway at the base of the dam until you’re almost touching the wall, then look to your left – a narrow path slips behind a rock and climbs steeply to the top.
You can cross the dam itself, though it’s technically private and gated at one end. The better view is from the ridge to the left, where you’ll find the classic overlook down the winding road – one of Snowdonia’s most photographed scenes. Cyclists regularly tackle the climb, and they make great subjects for action shots; just remember to keep your shutter speed high if you’re shooting in lower light.
To continue the walk, follow the left-hand edge of Llyn Stwlan, passing a beautiful old stone building – it’s a great spot to frame the valley through its doorway. The path then climbs steeply to the saddle.
Here the trail divides: the upper route ascends to the summit of Moelwyn Mawr (770 m) – a steep, exposed climb that’s best left to experienced mountain walkers. The alternative lower route curves along a higher terrace that skirts the back of Llyn Stwlan. Watch your footing here – at times it looks as though the path has vanished beneath the slate, but you’ll soon spot the terrace you’re aiming for ahead.
As you emerge from the far side, the hillside flattens and the path bears left into the old Rhosydd Quarry. The route then weaves through the quarry itself, passing stone buildings, arches and towering heaps of slate that rise dramatically on either side. Eventually, you’ll reach the main quarry complex – a vast area of walls, doorways and open windows that frame views down the valley towards Llyn Cwmorthin.
When it’s time to return, ignore the “shortcut” footpath marked on OS Maps between the quarry and Llyn Cwmorthin – it no longer exists and will lead you into fenced, uneven terrain. Stick instead to the old quarry road, which descends safely through the valley back to Tanygrisiau, offering superb final views across the slate country below.
The path to the top of Stwlan Dam isn’t marked clearly on OS Maps. To find it, walk under the archway at the base of the dam and look to your left — a narrow track climbs steeply behind a rock to the top.
You can walk across the dam, but it’s technically private and gated at one end. The ridge to the left gives a far better view down the road anyway.
For the classic photograph of the winding road, climb the ridge and walk back on yourself slightly. The overlook here gives you the best angle into the valley.
Cyclists are a common sight on the climb all year round — they make great subjects, but use a fast shutter speed to freeze motion on the bends.
The upper route to Moelwyn Mawr is steep and exposed; avoid it unless you’re an experienced mountain walker.
The Rhosydd Quarry ruins are fascinating but unstable — admire from the paths and don’t enter tunnels or shafts.
Ignore the “shortcut” shown on OS Maps between Rhosydd Quarry and Llyn Cwmorthin — it’s long gone. Stick to the old quarry road for a safer and more scenic descent.
If you’re short on time, there are two beautiful waterfall spots near the road up to the dam. One sits just below the main corner heading back to Tanygrisiau, and another larger fall flows from Llyn Cwmorthin near the start of the route — perfect for slow-shutter photography after rain.
This route rewards patience and an eye for detail rather than postcard-perfect compositions. The landscape here is rugged and functional — a mix of wild beauty and industrial legacy — so your challenge is to find balance and context within that.
The winding road below Stwlan Dam: This is the real star of the show. The best angle is from the ridge to the left of the dam, where you can look down over the sweeping switchback bends as they snake through the valley. Early morning or late afternoon light adds depth and texture, while cyclists on the climb give a strong sense of scale and movement.
Stwlan Dam itself: The dam’s stark, blocky concrete makes it a tricky subject. Try to include a foreground element — rocks, grass, or even a person — to anchor your shot and connect it to the surrounding landscape. Otherwise, focus your lens towards the valley and road below, which tell the story more effectively.
Llyn Stwlan: On its own, the lake can feel quite plain, but there’s a stone building on the hillside that transforms it into something special. Stand just inside the doorway and use the frame of the stone walls to look down towards the valley. It’s a simple composition that gives your image context and a sense of “lived-in” character.
Rhosydd Quarry: A moody, atmospheric area best shot under overcast skies or mist. The ruins and slate heaps work beautifully in black and white, and you can play with symmetry and geometry in the old walls and arches.
Llyn Cwmorthin: Time your visit for when the sun sets directly along the valley, lighting up the water and the surrounding slate in warm, golden tones. It’s worth waiting for — just look for foreground details like rocks, moss or puddles to anchor your shot and give depth to the reflection.
Great landscape photographs happen when you’re able to tie the landscape into a story. I often teach the idea of using an “anchor” object — something that connects you, the photographer, to that place at that moment. It could be a rock, a wall, a reflection or even your shadow. Ask yourself, what is anchoring me to this location today? Then weave that feeling into your composition.
If you’d prefer a shorter walk or want to mix in some waterfall photography, there are two beautiful spots close to the road up to Stwlan Dam that are well worth a visit.
After photographing the winding road from the ridge above the dam, head back down the road as if returning to Tanygrisiau. A few minutes after the main corner, you’ll see a stream crossing under the road from the left – a small but striking cascade framed by moss-covered rock and heather. It’s at its best after rain, and the flow makes a great subject for slow-shutter images if you’ve brought a tripod or stable surface.
Near the very start of the route, a larger series of waterfalls spills down from Llyn Cwmorthin, feeding the stream that runs through the village. You can reach it easily from the roadside before or after your main walk.
Both spots are easily accessed from the main road and can be enjoyed in under an hour, making them perfect for a quick shoot or a low-level photo stop if you don’t have time for the full Stwlan and Rhosydd circuit.
Don’t be tempted to make your shutter too slow. If the exposure drags, you’ll lose all sense of movement and the water turns to fog. Aim for a shutter speed that blurs the water but keeps the feeling of flow, and let the stream exit your frame through a corner — it helps the viewer’s eye follow the water naturally as it leaves the scene.
This is one of those rare locations that works in any weather. I’ve been up here in driving rain, thick mist, bright sunshine – each brings its own character to the landscape.
That said, autumn and winter are my favourite times to visit. In autumn, the grasses turn gold and copper, giving warmth and contrast to the grey slate. In winter, dramatic skies sweep across the valley and the low sun adds depth to the mountain ridges – plus, the climb is usually cooler and quieter than in summer.
If you do visit in winter, avoid the top route to Moelwyn Mawr unless you’re a confident and well-equipped mountain walker. Ice, wind and poor visibility can make the ridge sections dangerous, and it’s easy to misjudge your footing.
No matter the season, always pack for changeable weather – conditions here can turn quickly even on a seemingly clear day.
The weather around Stwlan Dam and Moelwyn Mawr can change in minutes — always carry warm, waterproof layers, food and water.
Take a paper OS map in case your phone battery dies, and install the What3Words app — it gives emergency services your exact location if you need help.
If you ever require assistance, dial 999 and ask for Mountain Rescue.
Always tell someone not on the walk where you’re going and when you plan to return. If they don’t hear from you afterwards, they can raise the alarm quickly.
As always in the hills, respect the weather – if it looks unsafe, turn back. The mountains will still be there next time.
You don’t need a car full of gear to enjoy this walk — just a few essentials to stay comfortable and make the most of the views.
Sturdy footwear: Walking boots or good trail shoes are ideal; expect uneven, rocky ground in places.
Warm, waterproof clothing: The weather here can change quickly even on clear days.
Snacks and water: There’s no café or shop once you leave Tanygrisiau.
Map and compass (or GPS): Always handy, even if you know the route.
Camera or phone: You’ll find plenty worth capturing, from the winding road to the quarry ruins.
(Optional) Tripod or filters: Nice to have if you plan to photograph the waterfalls or long exposures, but not essential.
Whether you’re here for the photos or simply the peace and quiet, this is a route that rewards slowing down and taking it all in.
The walk from Tanygrisiau up to Stwlan Dam, Moelwyn Mawr and Rhosydd Quarry captures everything I love about exploring with a camera — wild landscapes, layers of history, and views that change with every step. Whether you’re here to photograph it or simply to enjoy the journey, it’s one of North Wales’ most rewarding days out.
If you’d like a little guidance on the route, or want to combine the walk with hands-on photography tuition, I regularly lead group walks and one-to-one workshops here and across North Wales. I’ll handle the planning, tide times (where appropriate) and safety — you just bring your curiosity (and maybe your camera).
➡️ See upcoming walks and workshops here
Or if you’d prefer a more personal experience, I’m always happy to act as your private guide for a tailored walk or workshop — just get in touch to arrange something that suits your pace and interests.
I'm Liam, you're local photography guide, I've been running walks and workshops now for over 5 years, helping hundreds of walkers experience the great outdoors and always wearing my distinctive gold/yellow jacket!
I started this journey wanting to help those struggling with their mental health following the 2019 pandemic to get out into our countryside, using their cameras as an excuse to explore and I'm now heading into my 5th year!
My workshops are for everyone, beginners to experts, we'll always find something amazing to photograph together!
So whether you're new to photography or an experienced shooter, book one of my walks today, follow the golden jacket, and lets take great photos!
