Ordnance Survey
![Grid square TF from the Ordnance Survey National Grid, shown at a scale of 1:250,000. The map shows the Wash and the North Sea, as well as places within the counties of Lincolnshire, Cambridgeshire and Norfolk.](/Images/godic/202501/31/Ordnance_Survey_1-250000_-_TF0628.jpg")
![Part of an Ordnance Survey map, at the scale of one inch to the mile, from a New Popular Edition map published in 1946.](/Images/godic/202501/31/Grays_Thurrockmap_19460628.jpg")
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![Scan of the cover of the 5th series OS map Chelmsford and Southend sheet 108. Art by Ellis Martin.](/Images/godic/202501/31/Ellis_martin_5th_series0628.png")
Ordnance Survey (OS) is the national mapping agency for Great Britain and is one of the world's largest producers of maps. Since 1 April 2015 it has operated as Ordnance Survey Ltd, a government-owned company, 100% in public ownership. The Ordnance Survey Board remain accountable to the Secretary of State for Business Innovation and Skills. It is also a member of the Public Data Group.