The National Archives of Ireland completed digitization of 1901 and 1911 census records for all 32 counties, and records can be researched on-line: http://www.census.nationalarchives.ie/search/

The Irish government recently committed to introducing legislation which would allow publication of the 1926 census. In the meantime, however, here’s a description of records available for 1901 and 1911:

The returns for 1901 and 1911 are arranged by townland (the smallest division of land) or, in urban areas, by street.  The 1901 census lists, for every member of each household; name, age, sex, relationship to head of the household, religion, occupation, marital status and county or country of birth.  The census also records an individual’s ability to read or write and ability to speak the Irish language.  All of this information is given on Form A of the census, which was filled in and signed by the head of each household. Where the head of the household could not write, his or her mark, usually an X, was recorded and witnessed by the enumerator.

The same information was recorded in the 1911 census, with one significant addition: married women were required to state the number of years they had been married, the number of their children born alive and the number still living.

In addition to returns for every household in the country, both censuses contain returns for police and military barracks, public and private asylums, prisons, hospitals, workhouses, colleges, boarding schools and industrial schools among other institutions.

The returns for both censuses also give details of houses, recording the number of windows, type of roof and number of rooms occupied by each family.  Each house is also classified according to its overall condition.  The number of out-offices and farm buildings attached to each household is also given. This information is recorded by the enumerator, who provided summaries of the returns for each townland and street, including the religious denomination of occupants. These summaries include a list of heads of household, thus providing a nominal index for each townland or street.