The Ordnance Survey, as its name suggests, has its origins in the Board of Ordnance. Although the maps produced were originally created for military use, from the late 19th century onwards the Ordnance Survey produced maps for civilian as well as military purposes.

• 1716 - A Drawing Office was set up in the Tower to produce maps for military use

• 1745 - After the Jacobite uprising, George II commissioned a detailed map of the Highlands to facilitate planning campaign strategies against the Highland clans

• Late 18th and early 19th centuries - The Board of Ordnance produced maps of other parts of Britain. The Ordnance Survey is formally established

• 1841 - After a fire in the offices, the Ordnance Survey headquarters move from the Tower to Southampton where they remain to this day 

Important personalities

George III and the Ordnance Survey

It was during the reign of George III (1760-1820) that a new branch of the Board of Ordnance, the Ordnance Survey, came into being.

In the hopes of providing the military authorities with detailed maps that would be of strategic use in times of war, the Ordnance Survey gradually produced maps with greater detail of smaller areas.

By the end of the 18th century, King George feared that a French invasion under Napoleon was close at hand. Therefore the ability of the army to have a firm grasp of the terrain on which it would fight was essential. The first one-inch-to-one-mile scale map was produced in 1801 depicting the county of Kent. This was part of an ongoing project later known as the Principal Triangulation of Britain, in which accurate standard measurements of distances were determined throughout Britain between 1783 and 1853.