Loch Ness, Lake in Scotland, United Kingddom is the important lake. Loch Ness is a large, deep freshwater lake in the Scottish Highlands extending for approximately 37 km southwest of Inverness. Its surface is 15.8 meters above sea level. Loch Ness is best known for the alleged sightings of the legendary Loch Ness Monster, also known as "Nessie".