7.1
Wildland
Half day
Time
Check
Cost
Secluded
Feel
Why it's Wildland
7.1Known as the Black Lake, Llyn Dulyn sits beneath steep Carneddau cliffs. Its dark water and remote mountain setting are striking; at low water, wreckage from aircraft crashes has reportedly become visible.
A genuinely remote-feeling mountain lake reached by a demanding, rewarding circuit past another reservoir, old quarry remains and a bothy. The boggy ground, steep sections and exposed setting make this a proper hill walk, not a casual lakeside stroll.
Secluded · Dramatic · Atmospheric · Wild · Remote
Find your way
Open mapCarneddau, Eryri (Snowdonia), North Wales
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The experience
Come for the mountain setting and make the approach part of the experience: follow the circuit past Llyn Melynllyn, descend to Llyn Dulyn, pause by the bothy, then return through Cwm Dulyn. Expect boggy ground and steep sections; this is a hill walk, not a gentle waterside path.
Things to do
Walk the Llyn Melynllyn and Llyn Dulyn loop
A mountain circuit from Llyn Eigiau car park linking two reservoirs, the nearby bothy and the return valley. Expect rough, steep and potentially very boggy sections.
2.5–3 hours walking
Visit Dulyn Bothy
The mountain shelter lies close to the lake and is a natural pause on the circuit. It is a shared, unbookable bothy; check its current status and guidance before relying on it.
Look for the old quarry remains
The approach to Llyn Melynllyn passes the remains of Melynlynn Quarry Barracks and Melynllyn Mill.
Take in the lake’s dark-water setting
Pause to view Llyn Dulyn beneath the steep Carneddau cliffs. The Welsh name is translated in the route source as “black lake”.
Watch for aircraft wreckage when water levels are low
A route report says remains of crashed Second World War aircraft were visible when the reservoir level was particularly low. This is dependent on water levels; do not approach or disturb wreckage.
Make a day of it
Quick escape · Check before visiting
Reach the Black Lake
- 01
Start from Llyn Eigiau car park and follow the mountain route towards Llyn Melynllyn.
- 02
Continue on the path towards Llyn Dulyn, allowing time for the steep descent and rough ground.
- 03
Pause at the lake for the cliff-framed view, then return using a route you have checked in advance.
Half day · 2.5–3 hours walking; allow extra time for stops and conditions
Make a half day of the Carneddau circuit
- 01
Park at Llyn Eigiau car park and follow the ascent towards Llyn Melynllyn.
- 02
Notice the Melynlynn Quarry Barracks and Melynllyn Mill remains along the approach.
- 03
Continue to Llyn Dulyn and visit the nearby Dulyn Bothy.
- 04
Follow the return leg through the valley and alongside Afon Dulyn, allowing for boggy and steep ground.
Verified history
A walking guide reports that wreckage from Second World War aircraft crashes can be seen at Llyn Dulyn when the reservoir level is low. It relays a claim of eight aircraft crashes, attributed to Wikipedia, so that number is not independently established by the supplied sources. The route also passes remains identified as Melynlynn Quarry Barracks and Melynllyn Mill.
Folklore & legend
A walking article reproduces an account translated from a Welsh magazine printed in 1805. It describes the lake as exceptionally black, recounts strange-looking fish and says that wetting a distant stone called the Red Altar was believed to bring rain before nightfall. This is historical folklore, not a verified natural effect.
Hidden details
The Red Altar story — The supplied walking article quotes an 1805 account describing a stone causeway and a stone called yr Allawr Goch, or the Red Altar. The accompanying rain-making claim belongs to local folklore.
Quarry traces on the way to the lakes — The circular route passes the remains of Melynlynn Quarry Barracks and Melynllyn Mill before reaching Llyn Melynllyn and Llyn Dulyn.
When to go
March · April · May · June · July · August · September · October · November · Check the forecast and allow sufficient daylight for a remote mountain walk; no specific time-of-day recommendation is supported by the sources.
A route guide recommends March–November. The source row suggests late spring and early summer for milder weather and more accessible trails, while warning that winter may bring snow and ice. Boggy ground can persist even in dry summer conditions.
Conditions can change quickly in the mountains. The route includes steep, rough and boggy ground; use suitable footwear, check current weather and conditions, and carry navigation. Winter visits are recommended only for experienced hikers.
The route
- ascent
- 1,017 ft
- stiles
- A couple of stiles are reported; one route account describes a boggy metal stile.
- surface
- Gravel and unknown surface sections; rough, steep and boggy in places
- distance
- 5.8 miles
- duration
- 2.5–3 hours
- difficulty
- Moderate; rough, steep and boggy sections require care
- waymarking
- Check before visiting; the route source describes some paths as fainter than the main track.
- route shape
- Loop
- start point
- Llyn Eigiau car park
- parking start
- The route sources identify Llyn Eigiau car park as the start. The approach road is narrow and twisty; check parking and road access before travelling.
- shorter alternative
- A shorter route is not detailed in the supplied sources. Check a current map and local access information before attempting an alternative.
- Llyn Melynllyn and Llyn Dulyn
- Views towards the steep Carneddau cliffs
- Melynlynn Quarry Barracks and Melynllyn Mill remains
- Dulyn Bothy
- Return through the valley alongside Afon Dulyn
What to look for
- 01
Look for the contrast between the dark water and the steep cliffs, the remains of the Melynlynn Quarry Barracks and Melynllyn Mill on the approach, and the nearby Dulyn Bothy. Aircraft wreckage has reportedly been visible when reservoir levels are low
- 02
visibility will vary.
The story
Aviation; Industry
Best time to go
March–November for the circular walk; late spring and early summer bring milder conditions, while winter is for experienced walkers prepared for snow and ice.
Late spring and early summer are suggested for milder weather and more accessible trails. Autumn can be atmospheric, but conditions may be cooler and wetter. Winter visits are recommended only for experienced hikers.
How long to spend
Half day
Perfect for
Walkers · Photographers · Dogs
Practical information
Opening & access
A remote mountain destination reached on foot from Llyn Eigiau car park. The route includes steep, rough and boggy sections; check current access and conditions before setting out. Not wheelchair accessible. Access arrangements are unconfirmed. Check before visiting; do not enter private land or restricted structures.
Check before visiting
Parking
Llyn Eigiau car park is the stated starting point; the narrow approach road is twisty and includes gates. Check current parking and road conditions before travelling.
Check before visiting
Toilets
No toilets nearby; check before visiting.
Check before visiting
Food & drink
No cafés nearby; bring your own supplies.
Dogs
Dogs are welcome on the route; leads are advised where sheep are present. Stiles may be challenging for some dogs.
Accessibility
Not wheelchair accessible. The route has rough, steep and boggy sections, stiles and a substantial ascent; suitable footwear and navigation are important.
Cost
Check before visiting
Check before visiting
Water
Mountain reservoir
Gallery
Place photographs
Keep exploring
Around Llyn Dulyn
Within 50 km · approximate straight-line distances
