A view of the Mawddach Estuary on a clear spring day with woodland lining the shores.
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Tranquil lakes, hidden pools and raging waterfalls

Seeing a still mirror on the surface of a lake or a rushing river after a big flood is a mystical experience.

There is no shortage of water in the National Park. There are 434 miles of rivers and over 100 lakes.

There is little wonder that Eryri is known for its picturesque lakes and beautiful rivers, with over 4,000mm of rain falling on parts of the landscape annually.

Llyn Tegid
Llyn Tegid, Wales' largest natural lake
Llyn Tegid is the largest natural lake in Wales. It is a popular lake with swimmers, paddleboarders, anglers, canoeists and windsurfers. The lake lies in a beautiful valley surrounded by Y Berwyn, Yr Aran and the Arenig mountains. It covers 3.95 square miles, is three and a half miles long and up to half a mile wide.
Discover Llyn Tegid
Wildlife in Eryri's Lakes and Rivers
A small 'gwyniad' in the hands of
Gwyniad
This is one of Eryri's rarest species. These fish are native to Llyn Tegid after being trapped in the lake at the end of the last Ice Age.
A glutinous snail underwater
Glutinous Snail
Llyn Tegid, Y Bala, is the only place in the United Kingdom where the glutinous snail is found. This is a very rare organism throughout Europe.
Pearl mussels on a river bed
Freshwater Mussels
Freshwater mussels have a black or dark brown shell. They can grow up to 15cm long and are known for their dark coloured pearls.
Brown Trout
This is one of Eryri's most abundant fish. Brown trout have been swimming in the waters of the National Park since the Ice Age. They are often found in cold, clear water.
An otter on the shore of a river
Otters
Otters are mammals that live on the banks of rivers and lakes. They eat fish and tend to be very playful animals that play with pebbles to entertain themselves.
A water vole rests on the shore of a river
Water Voles
Water voles live on the banks of rivers, lakes and ponds. They tend to sit and eat in the same place and leave small mounds of grass at the water's edge.
A kingfisher rests on a branch
Kingfishers
Kingfishers are colourful birds that live by rivers and streams. They can be seen sitting on low branches above the water, diving in sharply to catch small fish.
An oystercatcher pertches on a craggy rock
© Ben Porter
Oystercatcher
The oystercatcher has a black head and wings and a white breast. They were originally coastal birds, but over the last 50 years, they have made use of waters and lakes.
A grey heron with a fish in its beak
© Ben Porter
Heron
The heron is a tall bird that can be seen standing still in shallow waters and catching fish with its long beak. They spend most of their time alone.
Lake names in Eryri

It is difficult to find a lake in Eryri that bears no significance, whether it is derived from the mythology and folklore of the area or from the features of the surrounding landscape.

Llyn Barfog, near Aberdyfi, is likely named after the rush that grows along its shores.

Legend has it that Llyn yr Afanc near Betws-y-Coed was named after a dangerous beaver.

This lake is believed to be named after a shepherd who drowned while washing his master’s sheep.

Llyn Bochlwyd, above Llyn Ogwen, is named after a tale about a stag fleeing from a hunter. It swam across the lake whilst holding its grey cheeks above the water to breathe.

Some believe that Llyn Tegid was named after Tegid Foel, a cruel legendary king. It is said that the kingdom of Tegid Foel was submerged because of his evil nature.