Castle Crag is a hill in the North Western Fells of the English Lake District. It is the smallest hill included in Alfred Wainwright's influential Pictorial Guide to the Lakeland Fells, the only Wainwright below 1,000 ft.
Wainwright accorded Castle Crag the status of a separate fell because it "is so magnificently independent, so ruggedly individual, so aggressively unashamed of its lack of inches, that less than justice would be done by relegating it to a paragraph in the High Spy chapter." Subsequent guidebooks have not always agreed- Castle Crag is one of only two Wainwrights not included in Bill Birkett's Complete Lakeland Fells.
High Spy, the parent fell, forms part of the north-south ridge between Borrowdale and the Newlands Valley. The rough spur of Low Scawdel (1,709 ft) runs out due east from the summit, breaking steeply over Goat Crag and then falling to Broadslack Gill. This small tributary of the River Derwent separates High Spy from Castle Crag.
The wooded height of Castle Crag rises between Broadslack Gill and the Derwent, the two streams meeting to the north beneath the outlying knoll of Low Hows. It has steep faces on all sides except the south, where a low ridge runs out and then swings west around the head of Broadslack Gill. A narrow col here provides the topographic link to High Spy.
The slopes of Castle Crag are extensively quarried with pits and levels on the northern and south eastern flanks. The summit has also been extensively worked. The High Hows Quarry later achieved fame as the home of Millican Dalton, the eccentric and self styled "Professor of Adventure". The caves here formed his summer home from the 1920s until shortly before his death in 1947.
There is a fine view down the valley, Skiddaw seen to good effect across the lake. Southwards Great Gable and the Scafells ring the head of the Derwent catchment, while near at hand- enhanced by the steepness of the slope- is a view of the woods and crags of mid Borrowdale.