Red Hills (centered on Marsco)
Use zoom controls to switch between 1:25,000 (explorer) and 1:50,000 (landranger) mapping.
Check magnetic variation (declination) using the British Geological Survey Grid Magnetic Angle Calculator- www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
Please note, these maps are provided to assist with route planning only. Always carry the relevant paper OS map together with a compass when navigating the fells and mountains.