Grasmoor is a mountain in the north-western part of the Lake District, northern England. It is the highest peak in a group of hills between the villages of Lorton, Braithwaite and Buttermere, and overlooks Crummock Water.
Grasmoor is distinguished by its steep western flank, dropping dramatically to Crummock Water. This face is however not suitable for rock climbers as there is little clean rock, although Alfred Wainwright describes a challenging route up the face in his Pictorial Guides to the Lakeland Fells. To the east the fell is linked to others by Crag Hill and Coledale Hause. Grasmoor is also home to the most extensive scree slopes in the North Western Fells.
The highest ground in the North Western Fells is an east-west ridge in this central sector, beginning with Grasmoor above Crummock Water and then gradually descending eastwards over Crag Hill, Sail, Scar Crags and Causey Pike. Grasmoor has the greatest elevation, although Crag Hill stands at the hub of the range.
From the valley floor near Little Town at the eastern end, the ridge requires four miles (6 km) of gradual ascent to attain the summit of Grasmoor. Starting at the shores of Crummock Water in the west, the same is achieved by a single slope of scree in less than a quarter of the distance. Grasmoor is Lakeland's terminal height par excellence.
The summit area is a gently domed promenade of moss and short grass, running along the ridgeline with a narrow constriction in the middle. This is created primarily by the scooped-out bowl of Dove Crags on the northern face. To the east of this plateau are broad smooth slopes descending to a wide unnamed col at . This connects onward to Crag Hill. At the western end the summit area narrows, culminating at the subsidiary top of Grasmoor End (2,445 ft) which crowns the western face. Great fans of scree descend to the lakeside road below. Grasmoor has one minor ridge which descends south westward over Lad Hows (1,397 ft) before a steeper fall to the valley floor.
To the south of Grasmoor is the valley of Rannerdale, which flows to Crummock Water between Lad Hows and the neighbouring Wandope. This drainage is supplemented by Cinderdale Beck, separating Lad Hows from the main body of the fell. The northern flank of the ridge stands above Liza Beck. This stream also makes due west for Crummock Water, but is diverted northward by the low top of Lanthwaite Hill to join the Cocker after its exit from the lake. An area of lowland to the north west is thus annexed to Grasmoor from the natural territory of Whiteside.
The obvious way is direct up the screes from Lanthwaite on the Crummock Water road, picking through the rock scenery above to appear on Grasmoor End from the north west. This involves of ascent in about half a mile. From the same starting point a detour along Liza Beck/ Gasgale Gill can be used to give access to the northern slopes. A way can then be found almost direct to the summit around the rim of Dove Crags. From Rannerdale a choice of routes arises, either climbing the Lad Hows ridge or following Red Gill a little to the west. Finally Coledale Hause can be used to gain the main ridge between Crag Hill and Grasmoor. This can be reached from Lanthwaite or as the first objective of a longer march from Braithwaite in the east. Coledale Hause connects to Hopegill Head and the fells to the north, providing further indirect possibilities. The summit was conquered by a Rolls Royce in 1982.