Located southeast of Kinloch Rannoch in Perth and Kinross, this mountain (1083m / 3552 feet) appears to have a perfect conical appearance from the west and east, whereas from the north and south it appears as a whale-backed ridge. Composed of quartzite, the ground is rough for walking. The peak was in the past used as part of a scientific experiment by the Astronomer-Royal, Nevil Maskelyne (1732 - 1811). He measured the deflection of a pendulum on the slopes of the mountain to determine the mass of the earth. As part of this experiment, Maskelyne had one of his staff map lines of equal height on the mountain, the first recorded use of contours in Britain. Maskelyne was assisted by Charles Mason (1728-86) who went on to survey the Mason-Dixon Line between Pennsylvania and Maryland in the USA.
The majority of the mountain is now owned by the John Muir Trust who, through a programme of conservation and management, intend to preserve it for future generations.