Am dan y warchodfa

The name 'Llyn Mawr' means 'big lake' in Welsh and it's this upland lake which forms the centrepiece of the reserve. The clear, unpolluted water supports a range of aquatic plants, such as Bogbean and Yellow Water-lily and even Quillwort, a rare plant in Montgomeryshire. The large expanse of open water provides the perfect refuge for water birds, such as Tufted Duck and the occasional winter visiting Whooper Swan.

The lake is surrounded by wetlands, supporting a range of bog, marsh and wet woodland communities. Visits on warm, sunny summer days can reward you with an abundance of dragonflies, damselflies and butterflies.

Llyn Mawr is designated a Site of Special Scientific Interest (SSSI) in recognition of the special lake and bog habitats.

As of 20th October 2023, Llyn Mawr Nature Reserve is a wildlife-only site and there is no public access. This nature reserve was not being given the respect it needed from many different reserve users, and due to continued prohibited activities, such as watersports, fishing, wild swimming and barbecues, along with anti-social behaviour, including uncontrolled dogs off leads, permissive access was understandably revoked by the landowner. Montgomeryshire Wildlife Trust was therefore left with no other choice than to close the site. Anyone found on the site may be liable to prosecution for trespassing by the landowner.