Sighty Crag is a hill in the southern part of the Kielder Forest region in northern England, a region which also includes its fellow Marilyns of Peel Fell and Larriston Fells. It is separated from its higher and more shapely counterpart, Peel Fell, by the low valley in which sits The Village of Kielder.
The hill is situated in a particularly remote part of northern Cumbria (although the Northumberland border runs over the north top just 600m from the top). It is four miles from the nearest road, making any walk to the summit and back at least eight miles long. Despite not being especially high, in terms of distance from civilisation it is the remotest Marilyn in the whole of England.