As many of the trails featured in this selection have information or starting points that are off the beaten track, the full Ordnance Survey map reference for the access point is given in the trail data panel.
A full Ordnance Survey reference consists of a two-letter code (example: SU) placing the reference within a particular 100 kilometre square of Britain and a group of six figures pinpointing the place within a 1 kilometre square of the map. The reference is useful on the Ordnance Survey 1:50 000 scale maps (e.g. the Tourist series) and 1:25 000 scale maps (e.g. the Leisure series).
The first three figures of the reference are called the the first two figures of the group indicate the western edge of the kilometre square in which the point lies (the grid lines are numbered top and bottom and on both sides of the map sheet). The third figure is the number of tenths of a kilometre the point lies to the east of that line.
The second set of three figures is called the contains a two-figure pointer to the southern edge of the kilometre square and a final figure indicating the tenths of a kilometre to the north of the line that the point lies.