Lakes, reservoirs and freshwater wetlands in the Brecon Beacons National Park

Our sparkling waters are glorious places to go walking, sailing and birdwatching, with a wealth of wildlife and scenery to inspire.


Some of the most beautiful lakes in the Brecon Beacons National Park are hidden away in the high cwms, or glacial valleys, of the mountains, where fresh water fills the hollows left by retreating glaciers in the last Ice Age.

High up in the Black Mountain range is the mysterious Llyn y Fan Fach, setting for the folk tale of The Lady of the Lake, and its near-neighbour Llyn y Fan Fawr. In the Central Beacons is a little gem of a lake which has fairy legend of its own, Llyn Cwm Llwch, which lies below Corn Du. A hike to any of these lakes will take you over rugged terrain, but your effort will be rewarded with magical scenery – and cool water to soothe hot feet!

East of Brecon, between the Central Beacons and the Black Mountains, is the largest natural lake in Wales, Llangorse Lake. Like the mountain lakes, it lies in a hollow formed by glacial action, but at 154m above sea level, it’s far more accessible. To find out more, visit our page on Llangorse Lake.


The Brecon Beacons National Park provides most of the drinking water for the population and industry of South Wales. Our reservoirs and dams, owned and managed by Dwr Cymru Welsh Water (, are striking additions to the natural landscape.

To the east of the Central Beacons is Talybont Reservoir, a Local Nature Reserve. No boating is allowed here, but it’s a wonderful spot for waterside walks, enjoying the tranquil atmosphere of the Caerfanell Valley. An easy access path starts from the large lay-by on the north-west side. To find out more, visit our pages on walking.

At the southern end of Talybont Reservoir is a bird hide overlooking a protected wetland area that floods in the winter, while not far from the dam at the northern end is the YHA Danywenallt National Park Study Centre, a converted farmhouse that’s just right for bringing a school group to the area.

In the Central Beacons, Pontsticill Reservoir, the largest of the Taff Fechan reservoirs, is surrounded by dramatic, forested hills. There's an attractive car park and picnic site on the west bank, which can be reached by a minor road from Merthyr to Talybont.

The Brecon Mountain Railway ( runs along the eastern shore of Pontsticill Reservoir.

The Merthyr Tydfil Sailing Club (, also on the eastern shore, is always looking out for new members to sail in this amazing setting. Watch out for the famous plug-hole though! To find out more, visit our page on sailing.

In the north-west of our Park, 320m above sea level, the Usk Reservoir fills a lonely valley in the shadow of the Black Mountain range. There is an excellent all-ability access point for canoeing at the north end of the dam, and an easier-access trail for a pleasant waterside walk or family mountain bike expedition. Keep your eyes open for red kites and buzzards which abound, but keep a weather eye open too – Atlantic gales feed straight in here!

Keepers Pond, a favourite local beauty spot, is easy to get to. Its car park is just off the B4246 from Abergavenny to Blaenavon. It was man-made around 150 years ago to supply water to Garnddyrys Forge in the valley below. You can admire the Black Mountains and the Central Beacons from here.

Groups can canoe or kayak in some of our reservoirs under certain conditions. To find out more, visit our page on canoeing.

Please remember that swimming in our reservoirs is not allowed except for when you capsize by accident, or during capsize and rescue training.

Freshwater wetlands

Wetlands are the richest and most diverse habitats found in the Brecon Beacons National Park. They provide for literally thousands of different insects, plants, birds and mammals.

High rainfall and the wide variety of landforms in our National Park gives rise to several different types of freshwater wetland. These include the reedbeds beside Llangorse Lake, the unusual rainwater-fed raised peat bogs of Traeth Mawr near the National Park Visitor Centre and the periodically flooded marshes of the river valleys. By their nature, wetlands can be awkward to access, but are superb places for birdwatching, wildlife-watching and plant-spotting. To find out more, visit our pages on wildlife-watching.