Explore the most perfect hanging valley in Snowdonia, its rock ledges and hanging gardens.
Distance 3 miles (4.8km)
Minimum time 2hrs 30min
Ascent/gradient 1,706ft (520m)
Level of difficulty Medium
Paths Well-defined paths, 2 stiles
Landscape High mountain cwm
Suggested map aqua3 OS Explorer OL17 Snowdon
Start/finish SH 649603
Dog friendliness Dogs should be on leads
Parking Small car park at Ogwen
Public toilets At car park
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1 The Cwm Idwal nature trail starts to the left of the toilet block at Ogwen and climbs up the hillside to pass some impressive waterfalls before turning right and continuing up the hill.
2 Go through a gate in a fence, that marks the boundary of the National Nature Reserve, and turn left along the side of Llyn Idwal's eastern shores. The clear footpath climbs into the dark shadows of Cwm Idwal.
3 Now you leave the nature trail, which turns right to complete a circuit around the lake. Instead ascend beneath the rock climbing grounds of the Idwal Slabs and across the stream of Nant Ifan, beyond which the footpath zig-zags up rough boulder ground to the foot of Twll Du - the Devil's Kitchen. If the weather, and preferably the forecast too, are fine climb to Llyn y Cwn at the top of this impressive defile, if not, skip this bit and go to Point 6.
4 To ascend Twll Du climb the engineered path as it angles left up the rock face, which will now be on your right-hand side, above an extensive area of scree and boulder. At the top you come to a relatively gentle (by comparison) grassy hollow between the rising summits of Y Garn, to the right, and Glyder Fawr, to the left.
5 Just beyond the first grassy mounds you come across the small tarn of Llyn y Cwn - the dog lake - which makes a great picnic spot. Now retrace your steps carefully to the bottom of Twll Du.
6 From here descend the rocky ground down to the western side of Llyn Idwal. The path reaches, then rounds, the northern shoreline to meet the outward route at the gate near the outflow stream, Point 2. Now follow the route of your outward journey back to the car park at Ogwen.
Shepherds say that Idwal is the haunt of demons and no bird dares fly over its damned water. In the 18th century, writer Thomas Pennant came here and said it was 'a place to inspire murderous thoughts, environed with horrible precipices', and it was here in the 12th century that Idwal, son of Owain Gwynedd, was brutally murdered by Dunawd, in whose care he had been entrusted.
If you come to this place on a day when the damp mountain mists swirl in and out of the blackened mossy crags, and when rain-soaked waterfalls drop from those mists like plumes of steam, you will experience the atmospheric menace. However, the sunshine can paint a very different picture, with golden rocks that are a playground for the modern-day climber and small mountain birds such as the wheatear and ring ouzel flitting through the breeze-blown grasses.
Cwm Idwal is a perfect hanging valley, a fine place to study geology and nature. In the last ice age a small glacier would have been slowly scouring its way over the cliffs at the head of the cwm before joining the huge glacier that used to fill the U-shaped valley of Nant Ffrancon. You pass the moraines (the debris left behind by the glacier) not long after leaving the car park at Ogwen.
The glaciation left a legacy in Idwal, for here in the inaccessible places free from animal grazing, rare plant species are to be found. These brought botanists from far and wide. Their favoured spots were the crags around Twll Du, otherwise known as the Devil's Kitchen, a deep defile where the mountainside's volcanic bedrock is divided by a column of basalt. Here was the snout of the glacier and, on the surrounding ledges and crevices, the rich soils allowed many species of Arctic plants to flourish. The most famous is the rare Snowdon lily, discovered in the 17th century by Edward Llwyd. Tufted and Arctic saxifrage are also here, but hard to spot, but the starry and mossy saxifrages are there for all to see, as are wood sorrel, wood anemone and oak ferns. Collectively, the foliage seems to flow down the rocks and you can see why it's called the Hanging Gardens.
Climbing above the rocks the path attains a wild and windswept hollow of moor grass and rushes. Llyn y Cwn (dog lake) is a shallow pool tucked beneath the loose boulder and shale slopes of Glyder Fawr. In summer bogbean rings the pool's outer edges with its pale pink blooms. This is a fine lofty place to dwell and admire the mountain views before going back down to the cauldron of Idwal.
Cobdens Hotel is a free house on the outskirts of Capel Curig. Meals might include Tandoori chicken, steaks and Welsh lamb. The popular Climbers Bar at the back of the hotel is actually built into the rock.
You will have seen moss campion in gardens all around Britain, but it flourishes here at Cwm Idwal too. You will recognise it by its abundance of beautiful pink five-petalled blooms and spiky leaves.
Penrhyn Castle appears to be a Norman castle, but looks are deceptive, for this one's Victorian. Built by architect Thomas Hopper for slate mogul George Dawkins-Pennant, the theme continues inside with a grand staircase, magnificent arches, fine paintings and stained-glass windows. Even the furniture imitates that used in Norman times. Open from late March to October, it's well worth seeing.