View from Bala
|Primary inflows||River Dee|
|Primary outflows||River Dee|
|Basin countries||United Kingdom|
|Max. length||3.7 mi (5.9 km)|
|Max. width||0.5 mi (0.8 km)|
|Surface area||1.87 mi2 (4.84 km2)|
|Max. depth||138 ft (42 m)|
|Official name||Llyn Tegid|
|Designated||7 November 1991|
Bala Lake ([ˈbala]; Welsh: Llyn Tegid, [ˈɬɨ̞n ˈtɛɡɨd]; also often known as Llyn Tegid to English speakers) is a lake in Gwynedd, Wales. The name Tegid may be related to Welsh teg, meaning "fair". It was the largest natural body of water in Wales before its level was raised by Thomas Telford to help support the flow of the Ellesmere Canal. It is 3.7 miles (6.0 km) long by 0.5 miles (0.8 km) wide, and is subject to sudden and dangerous floods. The River Dee runs through it and the waters of the lake are famously deep and clear. The town of Bala sits at its north-eastern end and the narrow gauge Bala Lake Railway runs for 3 miles (5 km) along the lake's south-eastern shore, and continues south-westward to the village of Llanuwchllyn (whose name means "above the lake").
The lake lies in a glacial valley which follows the Bala to Tal-y-Llyn fault line. The valley was blocked by a terminal moraine in the area of the village of Bala, thus forming the lake, which has remarkably straight and parallel sides.
Origins of name
George Borrow wrote of the lake in Wild Wales in 1856, "The lake has certainly not its name, which signifies 'Lake of Beauty', for nothing". In English the lake is named after the nearby town of Bala, whose name means "outlet of a lake" in Welsh. An older, now unused, English name for the lake is Pemble Mere or Pimble Mere (of which many variant spellings are recorded).
Bala Lake has abundant pike, perch, brown trout, roach, eel. It also contains the gwyniad, a fish unique to the locality and listed as critically endangered by the IUCN due to the introduction of the invasive and non native ruffe; and the very rare mollusc Myxas glutinosa (the glutinous snail). According to legend, whilst the Dee itself flows through the lake, the waters never mix. However this was not confirmed by the detailed limnological work undertaken from the 1990s, to understand and manage the occurrence of algal blooms on the lake. The lake now forms part of the River Dee regulation system and the level at its outflow is automatically controlled. Depending on flow conditions and the level of water in Llyn Celyn, water can flow either into or out of the lake at the normal outflow point.
In the 1990s the lake suffered from blooms of blue-green algae which indicated a significant and worrying eutrophication of the lake. Investigation by the Environment Agency in partnership with the water industry, the farming community and others has put in place a plan for reducing pollution inputs to the lake.
In the legend of the History of Taliesin, the character Tegid Foel ("Bald Tegid") was the husband of the goddess or witch Ceridwen. The place where his court stood is now beneath the waters of the lake. According to folk tradition, the court was drowned one night. It is said that the light of the court and the little town around it can be seen on a moonlit night.
The 3 Lakes Challenge
The 40-mile Three Lakes Challenge (or "Loch, Lake, Llyn") is a challenge first completed by a five-person relay of Sam Plum, Jason Betley, Helen Gibbs, Helen Liddle, and Debbie Taylor on 3–4 July 2015 under 'English Channel Rules'. The challenge involves swimming the length of Loch Awe in Scotland (25 miles), then driving to the Lake District and swimming the length of Windermere (10.5 miles), and finally driving to Wales and swimming the length of Llyn Tegid (3.7 miles). This new challenge, dubbed 'The 3 Lakes Challenge', is proposed as the swimming equivalent of the famous National Three Peaks Challenge.
Bala has two sailing clubs, and a number of companies provide kayaks, yachts and various other types of boats for hire. Aberystwyth University Sailing Club makes biannual trips to Bala Lake to allow sail training to take place in the winter months. 
- "Bala Lake". Retrieved 2010-01-26.
- "Bala Lake Railway". Retrieved 2010-01-26.
- Geiriadur Prifysgol Cymru. a–baldog. University of Wales. 2006. p. 648.
- Owen, H.W; Morgan, R. (2007). Dictionary of Place-names of Wales. Gomer Press.
- - Snowdonia Guide, Bala Lake website
- - Aberystwyth University Sailing Club