Irelands Valuation Office conducted it's first survey of property ownership in Ireland from 1848 to 1864. This survey became known as "Griffith's Valuation" after Richard Griffith, a Dublin geologist, who was the director of the office at that time. The survey was used to decide the amount of tax each person should pay towards the support of the poor within their poor law union. This involved determining the value of all lands and buildings in rural as well as urban areas to establish the rate at which each unit of property could be rented year after year.
Griffith's Valuation is arranged by counties and within counties by Poor Law Union Divisions and within Unions by parishes. It includes the following information:
However, it does not carry names of married sons or daughters for example, who may also occupy the property.
The first column heading is number and letters of reference to maps; the number refers to the location of the tenement on the 6’’ to-the-mile townland maps and equivalent town maps. Under the description of tenement, land and buildings are included, and, under net annual value, the annual rent expected, including maintenance and taxes but excluding the tithe rent. The information on towns is equally important, as the individual tenements were arranged according to streets. It is the only general assessment of land values in Ireland.
Griffith's Valuation can be used as an census substitute for the years after the Great Famine as all the censuses prior to 1901 were destroyed
The only directly useful family information supplied is in areas where a surname was particularly common. The surveyors often adopted the Gaelic practice of using the father's first name to distinguish between individuals of the same name, so that John Reilly (James) is the son of James, while John Reilly (Michael) is the son of Michael. Copies of the Valuation are widely available in major libraries and record offices, both on microfiche and in their original published form.
The Valuation was never intended as a census substitute, and if the 1851 census had survived, it would have little genealogical significance. As things stand, however, it gives the only detailed guide to where in Ireland people lived in the mid-19th century and the property they possessed. In addition, because the Valuation entries were revised at regular intervals, it is often possible to trace living descendants of those originally listed by Griffith.