 From there, the river runs westward, roughly aligned with the former Cockermouth, Keswick and Penrith Railway between Keswick and Penrith.The river subsequently flows through Keswick before joining the Derwent just after the latter flows out of Derwentwater.The medieval bridge over the river in Keswick was unusual in having two arches; on the great coach road from Kendal to Cockermouth all but two of the other bridges (Troutbeck and Portinscale) crossed their rivers in a single span.