5 Researching Irish history – using historic maps: exploring Geashill village, County Offaly since the 1830s


Researching Irish family history can be challenging due to the lack of written records. Owing to variation in the legislative union of Ireland, Scotland and Wales with England, registration of births, deaths and marriages was different in each country and comparatively late in Ireland. In Ireland, state registration of non-Catholic marriages began in 1845, but the registration of all births, marriages and deaths did not begin until 1864.   Additionally, Church records are often incomplete and those that exist are rarely found before 1800, particularly in rural areas.

There is a similar situation with census returns. The first census was taken in 1801 in England, Wales and Scotland but it was not until 1821 that it was taken in Ireland. The dearth of records was further compounded by destruction of records stored at the Four Courts in Dublin, either by fire in 1922 during the Civil war or census returns by being pulped soon after they were taken, probably due to a paper shortage.

However, one source of information that is available from the 1830s are the maps produced by the Ordnance Survey Office, Ireland, for the whole country.[1] The office had evolved from the Ordnance Survey Office which was established in 1824 and, as its name suggests, was part of the army under the Department of Defence.

The Ordnance Survey Office was created to carry out a survey of the entire island of Ireland to update land valuations for land taxation purposes. The townland boundaries were defined by a Boundary Commission. In addition to boundaries the maps are topographical, identifying such features as buildings, roads, streams and place names that were required for valuation purposes. Drawn at the large scale of six inches-to-one-mile (1:10,560) the original survey was completed in 1846 under the direction of Major General Colby. Ireland consequently became the first country in the world to be entirely mapped at such a detailed scale.

Working from north to south, the survey began in 1829 and was completed in Kerry in 1842. It was published as thirty-two county maps between 1832 and 1846. Completion year dates are available for each county withing the 1829-1842-year range. The first edition shows the land immediately before the Great Famine (1847-50) when the population was at the highest level ever recorded. The population of Ireland, which had numbered over eight million in the 1841 census, had been reduced by two million between 1845 and 1850, by a combination of emigration and deaths from starvation and disease.

When the first survey began it did not include field boundaries. This policy was reversed in 1838 after a number of northern counties had been published and so these counties in the north, we re-surveyed. Subsequently this general revision was extended to other counties because of change in the post Famine landscape. Survey work was curtailed in 1887 when the government agreed to survey the country at the larger scale of 1:2,500.

After the initiation of the 1:2,500 series most new editions of the six-inch map were reduced from the larger scale maps. In counties in the south of Ireland both the second and third editions were produced in this way. Only a small number of six-inch maps were produced by the Ordnance Survey of Ireland from 1930 to 1955 and most of these were for parts of counties, usually areas around the larger towns.

Historical maps can be a valuable tool in triangulation of data describing past interpretations of reality showing demographic changes, social and cultural changes to the landscape. They can be used for researching places and people. They give a time frame for dating buildings such as the history of  smaller ‘big’ houses that have stayed in private ownership and so less likely to have come under the scrutiny of the National Inventory of Architectural Heritage or  outside Landed Estates online database maintained by the National University of Ireland, Galway, which covers just Connacht and Munster. In relation to people, the maps can give a clear view of the population particularly when used alongside the Griffith’s Valuation. The maps were used as a basis for the primary valuation of Ireland, a rateable valuation of land and buildings carried out between 1848 and 1864 to determine liability to pay the Poor rate for the support of the poor within each Poor Law Union. It provided detailed information on where people lived in mid-nineteenth century Ireland and the property they possessed. It came to be known as the Griffith’s Valuation, named after its author Sir Richard Griffith (1784-1878).

The first edition of maps for Offaly was published in 1838, the second edition between 1884-5 and the third edition covered Offaly partially and was published between 1909 and 1910. Using the example of Geashill, and centred on the crossroads in facing North, the first edition of the map clearly shows Geashill Castle, St Mary’s Church of Ireland, the Police Barracks, Dispensary and the Post Office.

Image 1 – Geashill from Ordnance Survey map 1838

Image 1 – Geashill from Ordnance Survey map 1838


Image 2 Geashill – Griffith’s Valuation map based on Ordnance Survey map 1838

Image 2 Geashill – Griffith’s Valuation map based on Ordnance Survey map 1838

The numbers and letters on the Griffith’s Valuation, denote the reference to the maps In general, each townland is surrounded by a thick line on the map, with the numbered subdivisions outlined with lighter lines. For example, the Dispensary is within the area identified as 3 on the map

Image 3 – Extract from the Griffith’s valuation

Image 3 – Extract from the Griffith’s valuation

Image 4 Geashill from Ordnance Survey map 1884-5

The second edition of the map published for Offaly in 1884-5. It is clear that there a number of differences between the second and first editions, for example:

  • The reduction in cottages to the east of Main Street heading north
  • The change in the location of the dispensary from the north to the south of the Green
  • The new school building heading south of the crossroads

Image 4– Geashill from Ordnance Survey map 1884-5

The advantages of using the Ordnance Survey maps is enhanced by their free availability online via the Geohive website, which its webpage states ‘….is an initiative by Ordnance Survey Ireland to provide easy access to publicly available spatial data’. Additionally, the Griffith’s Valuation is available free on the AskAboutIreland website. It states that its website and the Cultural Heritage Project is ‘an initiative of public libraries together with local museums and archives in the digitisation and online publication of the original, the unusual and the unique material from their local studies’ collections to create a national Internet resource for culture.’


Sylvia Turner August 2020


AskAboutIreland available@ http://www.askaboutireland.ie/about-us/, accessed 14.08.2020

Ordnance Survey Ireland  – Historical mapping available @ https://www.osi.ie/products/professional-mapping/historical-mapping/ accessed 14.08.2020

Geohive available @ https://geohive.ie/ accessed 14.08.2020


[1] Ordnance Survey maps for Ireland were produced between 1829 and 1842 but were only produced for England and Wales over a period between 1842-1893 and for Scotland between 1843-1882.