The availability of Census data is one of the difficulties faced by researchers with Irish ancestry. Only two complete datasets (1901 and 1911) are available. These can be searched free at the National Archives site. Note that unlike in the UK, both sets of records are of the actual returns completed by householders.
Various fragments of the lost earlier Censuses (1821-91) have been collected and made available on other websites.
Various fragments of the lost earlier Censuses (1821-91) have been collected and made available on other websites.