Dun Hallin
Dun Hallin, a broch, is located just east of the settlement of Hallin. It occupies the southeast end of a steep-sided rocky plateau overlooking a fertile valley and the sea.
The broch has an internal diameter of around 10.5m and an external diameter of around 17.4m.
As well as the natural protection afforded by the rock stack the broch is additionally defended by a wall that runs round the perimeter of the stack enclosing an area about 40m from N to S and 50m transversely.
The broch has been constructed of large blocks of stone, the outer wall rising to a height of 3.4m.

The fort on the hill: comes from Gaelic and Norse. It is a prominent pre-historic stronghold being an Iron Age dun (700 BC - c550 AD)

Thanks to Pat Myhill for the picture.