The centerpiece of the Llyn Mawr Nature Reserve is the upland lake known as Llyn Mawr, which means 'big lake' in Welsh. It supports a diverse array of aquatic plants including Bogbean, Yellow Water-lily and the rare Quillwort, found only in Montgomeryshire.
Llyn Mawr is one of three lakes within a Site of Special Scientific Interest, situated high on the moorland plateau above the Carno Valley. At this spot you'll find a small boardwalk where you can enjoy close-up views of the lake.