Castle How is part of the ridge that lines the northern side of Great Langdale, starting at Huntingstile Crag above Elterwater and ending at Sergeant Man on the edge of the Langdale Pikes. This is an undulating ridge with a number of miniature summits, each running into the next. Castle How stands as a distinguishable fell out rather more on the ground than on the map.
The summit is a fairly sizable area of mixed ground, with a high point that is only a few feet above the level of the ridge to the west, but the ridge narrows as it heads towards Blea Rigg. The crags of Great Castle How and Little Castle How, facing north and east, give the fell impressive flanks. The walker coming west along the ridge sees Castle How as a nearly 400ft climb from Swinescar Pike, followed by a welcome plateau before the climb onto Blea Rigg.
Grid Reference of Summit: NY 307 075
Routes of Ascent
Castle How is normally climbed as part of the longer ridge walk, so is reached along the ridge-top path. It can be reached directly from both the north and south. From Great Langdale a steep path climbs up from Pye Howe into Swinescar Hause, then drops down the far side into Blindtarn Moss and Easedale. This path crosses the ridge path. The ridge can also be reached from Easedale Tarn, following a path that uses a gap in the crags to reach the ridge between Blea Rigg and Castle How.
Our walk from Silver How to the Langdale Pikes passes over Castle How.
The summit is just the highest of a series of rocky outcropping that litter the top of this fell. It can be found on the southern side of the ridge, a little away from the path.
Streams and Tarns
A series of nameless tarns run down the steep southern flanks of the fell into Great Langdale.
In the north Swinescar Hause flows into Blindtarn Moss, forming the eastern boundary of the fell. An unnamed beck forms the western boundary, running into Easedale Tarn. Between the two is Little Brinhowe Gill, which runs down into to Easedale, only joining Sourmilk Gill after the waterfalls.
Castle How can claim part of Easedale Tarn, which sits below its northern crags. It also has a number of small nameless tarns on the summit. To the north east is Blindtarn Moss, where an old tarn has slowly filled in and become a swamp.