How to read a British grid reference
A six-figure British grid reference identifies a 100-metre square. To meet someone at a junction in England, share the two letters for the area, the six digits and a feature you can both recognise. There can be several paths inside the same square.
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Find the two letters first
On an Ordnance Survey map, use the key to identify the 100 km square for your part of the walk. Put its two-letter code before the digits. Keep the letters when you copy the reference into a message because the same string of digits appears in other parts of Great Britain.
See the grid diagrams in Ordnance Survey’s map-reading booklet (PDF)
Read across, then up
Try an imaginary square with line 21 along its left side and line 35 along the bottom. A junction four tenths across and seven tenths up would read 214 357 after the letter prefix. The last digit in each group locates the junction within that kilometre. This is a practice example.
Agree which side of the bridge
A 100-metre square can include both riverbanks. Agree on a feature such as the west end of a footbridge beside the fingerpost. Send the full reference and the description together. Have your companion find it on their copy of the map before the group splits up.
Your plan, step by step
- Include both grid-square letters
- Write the three eastings digits before the three northings digits
- Add a landmark your group can see on arrival
Continue planning your trip
Reading elevation on the Swiss Via Francigena
Take your walk with you: download Appy
Explore maps, stages and elevation in the app, and plan your train or bus journey.
