In 1825 Richard Griffith was appointed by the British Government to carry out a survey of the general valuation of Ireland. He carried out two major valuation surveys: a townland valuation and a tenement survey which valued individual property. It is this second survey which is most concerned to genealogists because of the lack of census records before 1901. Griffith's Valuation is the closest we have to a census.
Below is the Valuation for the Townland of Glensharrold in Co. Limerick, completed in 1853. This was the townland that my Hanley ancestors lived in. Of the two columns of names in the record, the first is the list of "Occupiers" of pieces of property and the second is the "Immediate Lessors," i.e., the landlords. The record is somewhat difficult to read but looking at the second "Occupier" of land held by landlord, Thomas Carrol, you will see Mary Hanly. Although I have no proof, I suspect that this Mary Hanly is probably my 2nd great-grandmother - the mother of Thomas Hanley, my great-grandfather.