 Lank Rigg occupies an upland area about 2 miles square, bordered by the River Calder and Worm Gill to east and west.Worm Gill sweeps around the southern flank of the fell, joining the Calder at Thornholme to complete the moat on three sides.To the north east, via the subsidiary top of Whoap (1,676 ft), is a connection to the main ridge.