HISTORICAL ORDNANCE SURVEY MAPS

Ordnance Survey as a mapping agency has its origins in the military as it mapped the Scottish Highlands following the 1745 Jacobite rebellion.

During the French Revolution there were fears the war might reach our shores, so the government ordered the Board of Ordnance to survey England’s southern coasts.

Mapping started in 1747 and took eight years to complete. The Great Map was at a scale of 1:36 000 equivalent to 1.75 inches to a mile. All topographical information was recorded. The survey was carried out by parties of eight and relied on simple surveying compasses to measure angles and chains fifty feet long to measure distance between important features.

William Roy, a general in the Royal Engineers, was largely responsible for the starting point of the Principal Triangulation of Great Britain between 1783 and 1853; this then led to the creation of the Ordnance Survey itself. Work really began in 1790 when the Board of Ordnance began the national military survey.

In 1801, the first one-inch-to-the-mile map was published starting with the county of Kent followed by Essex shortly afterwards. The Essex maps were published by the Ordnance Survey and ignored the county border, whereas the Kent map was privately published.

During the next twenty years around a third of the country was mapped at the same scale, although by 1810, maps of most of the south of England were complete. By 1840, the one-inch ordnance survey maps covered Wales and some counties of northern England.

In 1855, the Board of Ordnance was disbanded and the Ordnance Survey became part of the War Office combining with the Topographical Survey and the Depot of Military Knowledge, both eventually transferring to the Office of Works.

The primary triangulation of the United Kingdom was completed by 1841 but was greatly improved in 1858. The Tithe Act 1836 led to a six-inch to the mile survey in England and Wales. This and the development of the railways resulted in the Ordnance Survey Act 1841 which granted a statutory right to enter property for the purpose of the survey.

From the 1840s, the Ordnance Survey concentrated on producing the County Series of maps by mapping the country, county by county, at a scale of six inches to the mile.

In 1854, twenty-five inch maps were introduced with a scale of 1:2500 and the six-inch maps were thereafter based on the twenty-five-inch maps. The first edition of these maps was completed by the 1890s, with a second edition completed in the 1900s. Publication of the popular one inch to the mile series for Great Britain was completed in 1891.

The Ordnance Survey also produced many restricted versions of the County Series maps for the War Office in a variety of scales which included details of dockyards, naval installations, fortifications and military camps. The War Department 1:2500 maps were contoured. They helped to complete the map-picture of pre-Second World War Britain.

From 1840, the six-inch scale was adopted in Great Britain and the 1:1056 scale was adopted for urban surveys. Between 1842 and 1895, some 400 towns were mapped at 1:500 with the remaining towns mapped at 1:2500.  The 1:1056 sheets were partially revised to provide the Land Registry index maps

Once Great Britain was successfully mapped, the Ordnance Survey sent their surveyors to Ireland to continue the project.

Map Scales - The 6-inch-to-the-mile maps (1:10,560) show rural landscapes with incredible detail, while 25-inch maps (1:2,500) provide in-depth detail for urban areas and land ownership. Many online maps are now "georeferenced," allowing them to be superimposed over modern maps.

As well as producing maps, the Ordnance Survey was responsible for the Public Boundary Archive for Great Britain. Its files show each change to a county, parish, parliamentary and local government boundary. There are large numbers of Ordnance Survey reports and other files describing and defining boundaries. They include:

Local government area boundaries 1852-1936

Poor Law Union boundaries 1820-1940

County boundaries

Ordnance Survey (OS) maps from the nineteenth and early twentieth century are essential for family history research allowing researchers to visualize ancestors' homes, workplaces, and neighbourhoods.

Locating Homes: Identify precise locations of homes listed in census records and locate churches, workplaces, schools and railways. The route of disused railways lines can also often be seen on the modern map.

Place names: you have found in the records will become a reality as will farm names and landed estates enabling you to form an impression of the character of the villages and towns which affected your ancestors' lives.

Churches and chapels: are denoted by different symbols depending on whether they have a tower, a spire or neither. The original church would occupy a dominant position. Places of worship without a spire or tower are more likely to be later and to be nonconformist chapels.

Town and village expansion: You can see housing patterns and how buildings are spaced and laid out. Discover if they were they next to industrial areas, sewage works and other potentially undesirable features or in suburbia with larger gardens. You will also be able to determine if streets were extended enabling you to approximate the construction date of your ancestor’s house.

Landowners sold off fields so you can clearly see the old field boundaries preserved in newer housing estates. In rural areas, fields are still shown on the map as well as paths and tracks and names of many of the smaller farms are shown.

You can also find evidence of old quarries for stone, sand, lime and other materials which may relate to the occupations listed for your ancestors.