How to describe features on a map?

Does anyone know any specific terminology for describing features on a map?

I need to say things like: 'The mountain is located on the southern part of the map, lining the footpath' and 'Leaving 10km width, trace the edge of the borderline and travel for about 100km to reach the town Knightsbridge just inside the point on the north side of the map.'

I need better words than 'northernmost' and to the 'west' to show the location of specific features eg. a river

Quite hard to understand what you mean without a picture.