Loch Lochy (Scottish Gaelic, Loch Lochaidh) is a large freshwater loch in Lochaber, Highland, Scotland. With a mean depth of 70 m (230 ft), it is the third deepest loch of Scotland. Located 16 km (10 mi) southwest of Loch Ness along the Great Glen, the loch is over 15 km (9 mi) long with an average width of about 1 km (0.6 mi). The River Lochy flows from its southwestern end while the Caledonian Canal links its northeastern extent to Loch Oich.
The Battle of the Shirts was fought at its northern end near Laggan in July 1544, between Clan Donald and Clan Fraser. The Stand-off at the Fords of Arkaig in September 1665 ended a 360-year feud between the Camerons and the Chattan Confederation. It took place at Achnacarry, on the isthmus between Loch Lochy and Loch Arkaig.
Folklore tales mention 'a supernatural being' called the River Horse which was said to emerge from the lake and assume a horse's shape before feeding on the loch's banks. The River Horse was also known as the Lord Of The Lake and the Water King and would overturn boats and 'entice mares from their pastures'. Another tradition was that of the River Bull, 'a gentle, harmless creature', who would 'emerge from the lake into the pasture of cows'. The Great Glen (Scottish Gaelic: An Gleann Mòr), also known as Glen Albyn (from the Scottish Gaelic Gleann Albainn "Glen of Scotland") or Glen More (from the Scottish Gaelic An Gleann Mòr) is a series of glens in Scotland running for 62 miles (100 km) from Inverness on the edge of Moray Firth, to Fort William at the head of Loch Linnhe.
The Great Glen follows a large geological fault known as the Great Glen Fault. It bisects the Scottish Highlands into the Grampian Mountains to the southeast and the Northwest Highlands to the northwest. The glen is a natural travelling route in the Highlands of Scotland, which is used by both the Caledonian Canal and the A82 road, which link the city of Inverness on the northeast coast with Fort William on the west coast. The Invergarry and Fort Augustus Railway was built in 1896 from the southern end of the glen to the southern end of Loch Ness, but was never extended to Inverness. The railway closed in 1947. Its strategic importance in controlling the Highland Scottish clans, particularly around the time of the Jacobite uprisings of the 18th century, is recognised by the presence of the towns of Fort William in the south, Fort Augustus in the middle of the Glen, and Fort George, just to the north of Inverness. Much of the glen is taken up with a series of lochs, with rivers connecting them. The Caledonian Canal also uses the lochs as part of the route, but the rivers are not navigable.