Census Records at National Archives
There are remnants of the 1821 Census of Ireland available for parts of a few counties and even fewer remnants of the 1851 census. What there is is indexed by place. Later 19th century census records were destroyed.
The 1901 and 1911 censuses are now available on line at
National Archives Censuses 1901 & 1911
This searchable database is now the primary starting point for people getting started on their family history.
As well as looking at Form A (essential), look also at Form B1 listing the surnames for the whole street or townland and Form B2, listing outhouses on farms mainly but also on other houses. Form B1 reveals whether or not the property was occupied or leased and you will also see data on the quality of the house, number of rooms, windows in front. You can compare the data on Forms B1 & 2 with the earlier data from the House Books of the Griffith Valuation to see how the farm developed - 1954 -1901 - 1911.