Ben Lui is the highest and most famous of a group of four Munros that lie south of Glen Lochy, and about 10 km north of the top end of Loch Lomond.

Ben Lui stands on the main watershed of Scotland, and is a 'nodal peak',[3] with its waters draining east to the Tay and North Sea, south to Loch Lomond and the Firth of Clyde, and west to the Lochy and Atlantic.

It also appears to stand at the head of Glen Fyne, but waters which may once have flowed south-west to it are now captured east with a 50-metre-wide separating bar only a few metres high.

An approach from the east allows for appreciation of the mountain's most celebrated feature, the rocky circular bowl of Coire Gaothaich.

By descending via the south east ridge the walker may elect to include Ben Oss (and possibly Beinn Dubhcraig) in the route before returning to the start.