National Grid (Britain)
system of geographic grid references used in Great Britain
On the streets of the UK's major cities, an address and a street atlas are probably all you need to locate places of interest. However a visitor intent on exploring rural parts England, Wales or Scotland will soon run up against the wide-spread use of national grid references. These are often found in guide-books, walking guides and even promotional leaflets, and usually look something like this:
- [SU921206], which is a location in the countryside just to the east of Midhurst, in West Sussex.

Most basic mapping in England, Wales and Scotland is undertaken by the Ordnance Survey. Maps published by the Ordnance Survey will certainly show national grid lines; most other maps are derived from Ordnance Survey mapping and will also probably show grid lines. This article is intended to explain how to locate a grid reference on a map using these grid lines. The Ordnance Survey created a PDF on understanding the national grid in Britain.