National Grid Historical Maps

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Product Description:

The Ordnance Survey’s National Grid historical maps were the map series published after the County Series, from 1943 onwards.  Previous maps were produced in the Cassini Grid projection but in 1935 the Re-triangulation of Great Britain began, alongside a decision that all OS maps and plans should be recast onto metric grid sheet lines using the Transverse Mercator projection, which led to the development of the OSGB36 datum and the National Grid reference system.  Progress was halted during the Second World War, but from 1945 work began on creating a new national map with urban areas surveyed at 1:1,250, rural at 1:2,500 and mountain and moorland at 1:10,000.  Up until 1962 the focus was largely on mapping urban areas at 1:1,250, but with the re-triangulation of Britain finally completed in this year the focus afterwards shifted to mapping rural areas at 1:2,500.  In 1969 the OS adopted a metrication programme which saw the old ‘six-inches-per-mile’ (1:10,560) replaced by the 1:10,000, the ‘one-inch-per-mile’ (1:63,360) by the 1:50,000, and the conversion of all contour lines, altitudes, and other measurements into metric units.  In 1980 came the completion of the resurvey and recasting of all mapping into the metric National Grid system, and efforts thereafter shifted to a process of continuous revision to ensure all maps were updated regularly.  A joint venture between the OS and Landmark has scanned the original paper map sheets and converted into a digital product as a series of georeferenced raster images.

Product Availability:

OS National Grid historic map datasets available through the Jisc Geospatial Platform service are summarised below.

The datasets are available with the following options:

  • Epoch – the maps have been grouped into five temporal ‘epochs’ which approximately correspond to the series of revisions originally issued
  • Map scale – maps are available at 1:1,250 for urban areas, 1:2,500 for rural areas, and 1:10,000 for mountain and moorland areas

Please note that the geographic coverage of each particular option varies depending upon the OS’s originally surveyed and published extent.


 Epoch  Approximate Version  Map Scale(s)  Publishing Year Range
 Epoch A5  First Survey/Overhaul to National Grid from 1945  1:1,250, 1:2,500, 1:10,000/10,560 1943-1993
 Epoch B6  1st National Grid Revision  1:1,250, 1:2,500, 1:10,000/10,560 1944-1993
 Epoch C7  2nd National Grid Revision  1:1,250, 1:2,500, 1:10,000/10,560 1946-1993
 Epoch D8  3rd National Grid Revision  1:1,250, 1:2,500, 1:10,000/10,560 1951-1992
 Epoch E9  3rd National Grid Revision  1:1,250, 1:2,500, 1:10,000/10,560 1953-1992


Dataset Thumbnail:


Dataset Specification:

Product Name

 National Grid historical maps

Data Provider

Landmark (originally Ordnance Survey)


1:1,250 (urban), 1:2,500 (rural), 1:10,000/10,560 (mountain and moorland)


Great Britain (complete)

Data Structure





Historical mapping


Landmark Licence

Update Frequency

Not updated


Dataset Resources:

OS Historical Resources Site
Landmark Historical Maps Site
NLS National Grid Maps Index Site