[2] About 35 kilometres (20 miles) long, it opens onto the Firth of Lorne at its southwestern end.

The southern part of the loch is wider, and its branch southeast of the island of Lismore is known as the Lynn of Lorne.

The town of Fort William lies at the northeast end of the loch, at the mouth of the River Lochy.

Allan MacDonald, an important figure in Scottish Gaelic literature, Loch Linnhe was said in local Scottish folklore to be the home of an each-uisge, or "water horse", whose back could accommodate all the children who wished to ride him.

Allan MacDonald later recalled that during his childhood in nearby Fort William, "Many's the horse I wouldn't get on as a child for fear it would be the each-uisge.