Loch Ness is the largest of three lakes located in the geological formation called the Great Glen, which divides the North of Scotland. Loch Ness is 23 miles long, a mile in width, and on average 600ft deep. The maximum depth recorded is 812ft, in an underwater cave called Nessies Lair. 6 major rivers flow into the lake, and continues out into the River Ness. Contains more than 2 cubic miles of fresh water. The lake is in a seismically active area, with an average of 3 earthquakes at Richter 4 per century.

The present day Loch Ness is about 10.000 years old, and was filled with water when a glacier filling the Great Glen withdrew at the end of the last Ice Age.

The lake is best known for the Loch Ness Monster, or Nessie, a myth dating back to a sighting in 1871.