Cader Idris is an impressive, culturally significant upland landscape. It is an area of special interest for its array of biological, geological and landform features. The massif itself comprises of corries, summit ridges, steep scree slopes and cliffs. Towards the south, there is a large U-shaped glaciated valley.
Cader Idris is one of the most southerly high mountains in the UK with many upland species reaching their southerly limit here, including the diminutive Dwarf Willow on the summit ridge. The area supports an extensive range of upland habitats including blanket bog, upland heath, broadleaved woodland and a variety of grassland types. Dwarf shrub heath is plentiful with Heather, Bilberry and Cross-leaved Heath common. Purple Moor-grass, Sheep’s Fescue and Common Bent are widespread in the grasslands. Llyn Cau is a nutrient-poor acid lake typical of upland Britain with few species but interestingly, Quillwort remains abundant. The crags and screes sustain clumps of bright green Parsley Fern. Mammals include Otter, Brown Hare, Water Vole and Lesser Horseshoe Bat. Breeding upland birds include Wheatear and Ring Ouzel (summer visitors), Peregrine, Raven, Skylark and Meadow Pipit.
The name ‘Cader Idris’, which translates as “the chair of Idris”, is widely believed to originate from Welsh mythology referring to ‘Idris the giant’, who used the mountain as an enormous armchair to stargaze. Alternatively, it may refer to Idris ap Gwyddno, a 7th-century Meirionnydd prince who defeated the Irish in battle on the mountain.
Cader Idris is also said to be the hunting grounds of Gwyn ap Nudd and his Cŵn Annwn. The howling of these dogs foretold death to the listener with the pack herding that person's soul into the underworld.
The Minffordd path to the mountain begins on the southern side near the Tal-y-llyn lake. A car park located behind the Minffordd hotel. The Pony path begins in the north, from the car park at Tŷ Nant.