is a

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

on the edge of the

Carneddau The (lit. 'the cairns'; is a Welsh language, Welsh plural form, and is sometimes anglicised to ''Carnedds'') are a group of mountains in Snowdonia, Wales. They include the largest contiguous areas of high ground (over or high) in England and W ...

range of mountains in

Snowdonia Snowdonia, or Eryri (), is a mountainous region and National parks of the United Kingdom, national park in North Wales. It contains all 15 mountains in Wales Welsh 3000s, over 3000 feet high, including the country's highest, Snowdon (), which i ...

North Wales North Wales ( ) is a Regions of Wales, region of Wales, encompassing its northernmost areas. It borders mid Wales to the south, England to the east, and the Irish Sea to the north and west. The area is highly mountainous and rural, with Snowdon ...

. The lake is in extent and deep. Less than a kilometre to its south lies the smaller Llyn Melynllyn. Cliffs rise steeply from the lake edge up to the summits of Garnedd Uchaf and Foel Grach, giving it a dark brooding appearance - hence its name. The lake was dammed in 1881, to increase its capacity, and was significantly altered in 1931 by Llandudno Waterworks.As a reservoir Dulyn (along with Melynllyn) provided water for the town of

Llandudno Llandudno (, ) is a seaside resort, town and community (Wales), community in Conwy County Borough, Wales, located on the Creuddyn peninsula, which protrudes into the Irish Sea. In the 2021 United Kingdom census, 2021 UK census, the community � ...

. The reservoir was repurposed in 1997 for use as hydroelectric generation. The outflow from the lake, the Afon Dulyn, also feeds water into neighbouring

Llyn Eigiau Llyn Eigiau is a lake on the edge of the Carneddau range of mountains in Snowdonia, Conwy, Wales. The name ''Eigiau'' is thought to refer to the shoals of fish which once lived here. Early maps refer to it as ''Llynyga''. It is thought that ...

. Afon Dulyn flows north-east, passing Tal-y-bont before joining the

River Conwy The River Conwy (; ) is a river in north Wales. From its source to its discharge in Conwy Bay it is long and drains an area of 678 square km. "Conwy" was formerly anglicised as "Conway." The name 'Conwy' derives from the old Welsh words ''c ...

. The cwm has been the site of a number of aeroplane crashes including that of an American Dakota aircraft which crashed into the cliffs above the lake in 1944 killing all four crew.

Folklore

Marc Morris, in his biography of King

Edward I of England Edward I (17/18 June 1239 – 7 July 1307), also known as Edward Longshanks and the Hammer of the Scots (Latin: Malleus Scotorum), was King of England from 1272 to 1307. Concurrently, he was Lord of Ireland, and from 1254 ...

, claims that in June 1284 Llyn Cwm Dulyn was the setting for the court of the king for victory celebrations, following his defeat of

Llywelyn ap Gruffudd Llywelyn ap Gruffudd ( – 11 December 1282), also known as Llywelyn II and Llywelyn the Last (), was List of rulers of Gwynedd, Prince of Gwynedd, and later was recognised as the Prince of Wales (; ) from 1258 until his death at Cilmeri in 128 ...

, with an Arthurian theme, including the King's 45th birthday. "Back in Wales, the search for symbols of conquest and the celebration of victory continued in a similarly Arthurian vein, For most of June, including his forty-fifth birthday, the king chose to keep his court at Llyn Cwm Dulyn, a deep, dark lake in the mountains to the south of Caernarfon, reputed to have mystical properties." That lake, with a similar name, should not be confused with Llyn Dulyn, which is located more than fifteen miles as the crow flies northeast. A stone

causeway A causeway is a track, road or railway on the upper point of an embankment across "a low, or wet place, or piece of water". It can be constructed of earth, masonry, wood, or concrete. One of the earliest known wooden causeways is the Sweet T ...

(now underwater) once led into the lake. At the end of the causeway was a stone known as the Red Altar. Tradition states that if a person poured water on the altar then it would rain within a day.Trevelyan, Marie (1909), ''Folklore and Folk Stories of Wales'', p. 12. It is also said that if a person stands at the edge of the lake on one of the three "spirit nights" (including

Halloween Halloween, or Hallowe'en (less commonly known as Allhalloween, All Hallows' Eve, or All Saints' Eve), is a celebration geography of Halloween, observed in many countries on 31 October, the eve of the Western Christianity, Western Christian f ...

), then he or she will see images in the water of those who will die within the year.Trevelyan (1909), p. 13. It is further said that people who have led evil lives are sometimes dragged by

demon A demon is a malevolent supernatural entity. Historically, belief in demons, or stories about demons, occurs in folklore, mythology, religion, occultism, and literature; these beliefs are reflected in Media (communication), media including f ...

s down into the black waters of the lake. A local

witch Witchcraft is the use of magic by a person called a witch. Traditionally, "witchcraft" means the use of magic to inflict supernatural harm or misfortune on others, and this remains the most common and widespread meaning. According to ''Enc ...

who mysteriously disappeared is said to have suffered this fate.

References

*"The Lakes of North Wales" by Jonah Jones, Whittet Books Ltd, 1987 {{authority control Caerhun Dulyn Dulyn Aviation accidents and incidents locations in Wales