The lake viewed from the southwest
|Basin countries||United Kingdom|
|Surface area||1.53 km²|
|Surface elevation||154 m|
Llangorse Lake (Welsh: Llyn Syfaddon, variant: Llyn Syfaddan) is the largest natural lake in South Wales, and is situated in the Brecon Beacons National Park, near to the town of Brecon and the village of Llangors.
The lake is famous for its coarse fishing (particularly pike), watersports, the afanc (nicknamed 'Gorsey') and the only example of a crannog in Wales. Llangorse lake is also one of the most mentioned sites in Welsh folklore. It is a site of international conservation importance.
Due to Llangorse Lake's long history of human activity it has been known by several different names during its history both in the Welsh language and in English, other names include the lake's original Welsh name, Llyn Syfaddon/Syfaddan, and Brycheiniog Mere, (the English name Llangorse Lake is comparatively recent).
Llangorse Lake is a eutrophic glacial lake with a 5 miles (8.0 km) circumference covering an area of 327 acres (1.32 km2). The lake is 1-mile (1.6 km) long and 505 feet (154 m) above sea level. The lake is sited between the basins of the River Wye to the north and the River Usk to the south and was formed by debris deposited by melting glaciers trapping water on a plateau over time. The Afon Llynfi provides the main input of water into the lake and continues as the lake overflow stream.
Natural history 
The lake is a Site of Special Scientific Interest (SSSI) and has long been regarded as a place where fish and birds are found in unusually high numbers. Gerald of Wales (Giraldus Cambrensis) mentioned the abundance of waterfowl in his topographical work, The Description of Wales² in the 12th century A.D.. It is a Special Area of Conservation (under the EU Habitats Directive) as an example of a natural nutrient-rich lake with pondweeds.
The supposed largest pike caught by rod in the UK was caught in Llangorse Lake in 1846 by O. Owen and weighed 68 pounds (31 kg). The weight of this particular fish is unsubstantiated, however. If true this would have been the largest pike in the world so seems somewhat doubtful. The largest pike in the UK was actually caught from Llandegfedd Reservoir near Pontypool and weighed 46 pounds (21 kg). More recently the skull of a pike of unknown weight, though undoubtedly large (35–40+ lb), was found on the shores of the lake in 2004, this was taken away by the Environment Agency for Age Testing.
The Llangasty Nature Reserve forms an important protected area around the lake's boundary.
The lake is a habitat for the Scarce Blue-tailed Damselfly (Ishnura pumilio).
The crannóg is a small artificial island about 40 metres from the north shore. It is constructed of massive planks of oak behind which was built a dwelling platform formed from layers of stone, soil and brushwood. It was investigated by archaeologists from the National Museum of Wales between 1989 and 1993. Finds included a high quality textile and a bronze hinge from an 8th–9th century reliquary decorated in a style similar to that seen in Ireland. The 1993 dig was joined by the TV series Time Team and featured in series one, episode four in 1994. In 2005, works were carried out to protect the island from erosion.
Dugout boat 
Llangorse Lake in literature 
As Lake Leucara, the lake (and surrounding area) features in the works of Raymond Williams, who wrote People of the Black Mountains detailing the lives of ordinary people in the area at intervals from 30,000 years ago through to mediaeval times.
Gorsey, the Afanc of Llangorse Lake 
The Afanc would have been well known in local folklore at the time of the composition of the poem and is still sighted to this day.
Oll Lewis, an ecologist and cryptozoologist in the Centre for Fortean Zoology has been studying the Afanc of Llangorse Lake for several years has proposed the hypothesis that the Afanc may be sightings of the abnormally large pike of the lake. Adrian Lloyd Jones of the Welsh Beaver Project believes that Afanc stories in Wales are folk memories of the presence of beavers. (The modern Welsh word for beaver is afanc).
See also 
- Llangorse lake in the Brecon Beacons national park
- The Monster of Llangorse Lake documentary by Oll Lewis
- BBC News Mid Wales, Hundreds of water voles released near Llangorse Lake
- Keen, Richard and Burgum, Ian. Wales. Orion Publishing Company (1997) pg. 134.
- "Rescuing Llangors Crannog". British Archaeology (84). September/October 2005. Retrieved 2009-08-08.
- "Prehistoric Britain - Crannogs". Channel 4. Retrieved 2009-08-08.
- The Description of Wales by Geraldus Cambrensis at Project Gutenberg
- The Domesday Book of Mammoth Pike by Fred Buller, Hutchinson, 1979 (ISBN 0-09-136170-2)
- Brecon Beacons national park information at the mountain hut
- S.S.S.I. listing
- 'The Description of Wales' by Giraldus Cambrensis at Project Gutenberg
- www.geograph.co.uk : photos of Llangorse Lake and surrounding area