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 North Western Fells occupy the area between the rivers Derwent and Cocker, a broadly oval swathe of hilly country, elongated on a north-south axis. Two roads cross from east to west, dividing the fells into three convenient groups. The central sector, rising between Whinlatter Pass and Newlands Pass, includes Grasmoor.