The reserve is owned & managed by the Wildlife Trust and is made up of ancient, broadleaved woodlands of oak, birch and ash trees.
Within the reserve is an old ruined cottage belonging to former mine owner, Morgan Thomas, who lived here 100 years ago.
Iron ore was once mined here but the tramways that used to cart away the ore, coal and charcoal are now covered with mosses and wild flowers.
The are is full of myths and legends. Supposedly the water bubbling up from Ffynnon Gruffydd is said to have healing properties and fairies dance here on Hallowe'en. The ghost Y Brenin Llywd (King of the Mist) haunts the old mine and there's also a one-armed ghost of a man who apparently committed suicide at the cottage in 1930.