It runs some 100 kilometres in an North-east to South-west direction. Only one third of the entire length is man-made, the rest being formed by Loch Dochfour, Loch Ness, Loch Oich, and Loch Lochy. These lochs are part of the Great Glen, a fault in the Earth's crust. There are 29 locks, four aqueducts and 10 bridges in the course of the canal.
The canal was designed by engineer Thomas Telford and built between 1803 and 1822. Formerly of great importance for merchant and naval traffic, the canal is now mainly used by pleasure craft. It is maintained and run by British Waterways Board, a governmental organisation.