The Northern Fells occupy a circular area about 10 miles in diameter. The centre is slightly lower, an area of upland grazing and marshland known as Skiddaw Forest. This name may be misleading since the only trees form the windbreak of Skiddaw House. This isolated building, was once a shepherd's bothy. It currently serves as a youth hostel. Skiddaw Forest stands at the head of the three major rivers of the Northern Fells. The Caldew, Dash Beck and the Glenderaterra. These streams divide the circular area into three distinct sections.