The dramatic name was coined by early visitors to the valley, who found cliffs towering above the road, and the river rushing just beneath an exhilarating thrill.
The road and river certainly twist and turn around the crags at this point, vyeing with each other for the minimal flat ground at the valley bottom and the native Atlantic Oak Wood adds to the intimate, 'enclosed' atmosphere.
The teeth in the jaws
Castle Crag, one of the pointed jagged 'teeth' in the jaws offers a few choices for exploring the area which Wainwright called 'the loveliest square mile in Lakeland'.
The walk to the summit is less demanding than it first appears and offers wide-ranging views over Derwent Water and Skiddaw to the north, or to Upper Borrowdale and Great End to the south.
War memorial mountain
As well as being an iron-age hill fort and a 19th century slate quarry, the summit of Castle Crag was also given to the National Trust as a war memorial after the First World War. It was given by the family of 2nd Lieutenant John Hamer. Hamer was killed in action in March 1918, and the memorial is dedicated to him and to 'the men of Borrowdale' who lost their lives in the First World War, and whose names appear on the stone tablet.
Walking along the river
The riverside walk that meanders around the base of Castle Crag takes you beside lazy swimming holes with shingle beaches, and beside swift rapids as you walk between Rosthwaite and Grange.
From the National Trust car park at Bowder Stone (CA12 5XA), a gentle ten minute stroll through the woods will take you to the most famous boulder in Lakeland, the Bowder Stone, a natural tourist attraction for the past 250 years.
Elsewhere, deeper delving will reveal ancient quarry workings. Nature is gradually reclaiming these, forming interesting new habitats. One disused example was used as a summer home by Millican Dalton the self styled 'Professor of Adventure'.
