Not strictly defined, the hills form a lightly curving southwest-northeast shape and cover a considerable area. The Ettrick valley to the east separates them from the Craik Forest and the western border follows the A708 road. The large area west of Hawick, southwest of Selkirk and south of Yarrow Water could also be said to be part of the range as well as part of the historic Ettrick Forest. The hills are relatively low-lying for the counties in which they lie, with the highest summit, Ettrick Pen, being 692m, however, unlike other nearby ranges, could be said to follow a definitive direction. The highest hills are on the western extremity of the area.