Loch Ness takes its name from the River Ness which flows from the northern end of the loch. William Mac Kay in his book Urquhart and Glenmoriston: Olden times in a highland Parish, published in 1914, states that the origin of the name derives from an ancient Scottish legend which contains the phrase Tha loch 'nis ann, tha loch 'nis ann !" (There's a lake now, there's a lake now!).
The river is connected at its southern end by the River Oich and the Caledonian Canal to Loch Oich. At its northern end is the Bona Narrows, which opens into Loch Dochfour, which feeds the River Ness and a further section of the canal to Inverness, eventually leading to the North Sea via the Moray Firth.
It is one of a number of murky, interconnected bodies of water in Scotland; its visibility in water is exceptionally low due to the high peat content in the surrounding soil. At 56 km² Loch Ness is Scotland's second largest lake by surface area after Loch Lomond, however due to its great depth it is the largest by volume in the British Isles.
Its deepest point is 230m, making it Scotland's second deepest loch after Loch Morar. A 2016 survey claimed to have discovered a fissure extending to a depth of 271m, but further research determined it to be a sonar anomaly.
It holds more water than all the lakes in England and Wales combined and is the largest body of water in the Great Glen valley, which runs from Inverness in the north to Fort William in the south.
Loch Ness: geology, features, myths and legends
At the southwestern end of the lake, near Fort Augustus, is an island, Cherry Island.
It is a crannóg and was probably built during the Iron Age. Previously there was a second island, Dog Island, but this was submerged when the water level was raised during the construction of the Caledonian Canal. In Drumnadrochit is the Loch Ness Center and Exhibition, which examines the natural history and legend of Loch Ness.
Boat cruises operate from various lakeside locations, giving visitors a chance to search for the monster. Urquhart Castle is located on the west coast, 2km east of Drumnadrochit. Loch Ness is known as the home of Ness, a cryptid.
It is similar to other alleged lake monsters from Scotland and the rest of the world, although its description varies from one account to another. Popular interest in and belief in the animal's existence changed when it was first brought to national attention in 1933 and worldwide in 1934, following the publication of two photos, purported to prove the cryptid's existence, the second of a model snake neck mounted on a toy submarine.
Loch Ness serves as the lower storage reservoir for the Foyers pumped storage hydroelectric scheme which was the first of its kind in the UK. The turbines were originally used to provide power to a nearby aluminum smelting plant, but now electricity is generated and supplied to the national grid.
Another scheme, the 100-megawatt Glendoe Hydro Scheme, near Fort Augustus, began production in June 2009, subject to a downtime between 2009 and 2012 for repairs to tunnels connecting the reservoir to the turbines. At the southwest end of the lake, near Fort Augustus, are some crannógs.
Loch Ness lies along the Great Glen Fault, which forms a line of weakness in the rocks carved by glacial erosions, forming the valley of the same name and the basins of Loch Lochy, Loch Oich and Loch Ness.