This rises gently at first past High Nook farm, before accelerating its climb up the face of Black Crag to the summit plateau.

A subsidiary top at 1,601 ft (488 m) is reached first, unnamed on Ordnance Survey maps but referred to as High Nook in some guidebooks.

[2] The ridge widens, damply, and turns south at the summit, dropping over a rough patch of ground named White Oak.

These merge beneath the nose of the ridge at High Nook Farm, before joining Dub Beck, the outflow of Loweswater.

One of the feeders of Highnook Beck is High Nook Tarn, a small pool with a low earth dam.

A long brooding pool with a depth of about 12 ft (4 m), Floutern Tarn drains east and then north into the morass of Mosedale.

From Croasdale the west ridge of Banna Fell can be used, although entailing a roundabout route, as walkers are no longer welcome to use the more direct line up Croasdale Beck to White Oak (this route has now been omitted from the revised edition of Wainwright's guide to the Western Fells).