 Wainwright divided the fells into seven geographical areas, each surrounded by valleys and low passes.While any such division must be arbitrary- and later writers have deviated to a greater or lesser extent from this blueprint- Wainwright's sevenfold division remains the best known partitioning of the fells into 'sub ranges', each with its own characteristics.The North Western Fells are one of these divisions, covered by volume 6 of Wainwright's work.