Irish Townland Maps
Ordnance Survey maps of Ireland, surveyed between 1829 and 1843
By the early 19th century it was becoming apparent to the British Parliament that Ireland’s local taxation system, the "County Cess", was outdated and unusable. The County Cess was based on ancient land units known as Townlands which had for centuries provided the framework for society throughout Ireland and was how local community delimited and identified itself. The main problem was that whilst the names and limits of the Townlands were reasonably well known, the accurate acreage and subsequently the rateable value were uncertain.
In 1824 the director of the Ordnance Survey (OS), Lt Col Thomas Colby, was authorised by the British Parliament to undertake a survey of all of Ireland at a scale of 6 inches to 1 statute mile as part of planned reforms to Ireland’s taxation system. Such a detailed nationwide mapping survey had never been attempted anywhere in the world before.
Although the OS was tasked with accurately surveying the country, including the Townlands, in 1825 a new Government boundary department was created under the direction of Richard Griffith. Their job was to ascertain and sketch all Townland, Parish, Barony and County boundaries ahead of the main OS surveyors who would follow up by surveying the boundaries and then accurately measure the acreages.
Work commenced in the north of the country and progressed south with each county in turn being surveyed, drawn, engraved and published. The time taken between the survey of a county being completed and it being published was normally around 3 years.
Many technical advances and innovations were developed during the 6 inch survey of Ireland as it was the first time an entire country had been mapped at such a large scale. These advances and the quality of the copper plate engraving meant that when the maps were published between 1833 and 1846, they were arguably the most detailed, accurate and beautiful ever produced.
The Griffith's Valuation
Using the output from the mapping survey, Richard Griffith went on to oversee the Primary Valuation of Tenements, carried out between 1847 and 1864, which determined not just the value but also the occupiers of all lands and buildings. The results were collated into the General Valuation of Rateable Property in Ireland, more commonly known as the Griffith’s Valuation. This valuation, directly linked to the 6 inch maps, has become an invaluable resource to historians and genealogists in searching for Irish ancestors and finding out how they lived.