Keswick is in the lee of the Skiddaw group, the oldest group of rocks in the Lake District. These fells were formed during the Ordovician period, 488 to 443 million years ago; they form a triangle sheltering the town, reaching a maximum height of 931m on Skiddaw itself. To the west of Portinscale, to the south-west of the village of Thornthwaite, is Whinlatter Forest Park and Grisedale Pike. To the east, beyond Castlerigg stone circle, is St John's in the Vale, at the foot of the Helvellyn range, which is popular with ramblers starting from Keswick. In 2010, Electricity North West, United Utilities, the Lake District National Park Authority and the conservation charity Friends of the Lake District invested £100,000 to remove power lines and replace them with underground cables, to improve the quality of scenery in the vicinity.