The National Archives of Ireland has made available free online in digital format the Irish censuses for 1901 and 1911. The search page is easy to use. You can select which census year; 1901 or 1911 and place just a surname if desired. If it is a common Irish name, more details, such as a given name, male or female or approximate age in the census year would be helpful to narrow the search. The two censuses with over 9 million names covers all of Ireland, including the counties of Northern Ireland; such as Down, Londonderry, Antrim, Tyrone, Armagh and Fermanagh.
Both of these early 20th century Irish censuses have each household listed in all the counties. Within each household are the individuals in the house with their name, age, sex, relationship to head of the household, religion, occupation, marital status and county or country of birth. The census also indicates an individual’s ability to read or write and ability to speak the Irish language. Added to the 1911 census was concerning married women and how many years they had been married, along with the number of their children born alive and the number still living as of 1911.
Not just households were counted, but the military posts, prisons, workhouses, hospitals, institutions, colleges and boarding schools. An interesting aspect to the censuses was the information on the house that was requested. Such items included on the census schedule were the number of windows, the number of rooms occupied, the condition of the house and the roof type.
Once a certain name is located on the index you can click on that name to see all the other individuals in the household. Not only would all the requested information be written out, but even the exact house number and street address, if it was available. The transcription is what is viewed first. There can be spelling mistakes and variations in name based on the way a transcriber read the original census.
However, the site also has the scanned image of that original census document and the full household. That way you can see first-hand what was written more than a hundred years ago concerning an Irish ancestor. The scanned images include the enumerator’s abstract about individual's religion, along with other details and the house description.
A special addition to the site are the gallery of photo images of certain Irish locations. Those places shown in photos along with descriptions are Cork, Dublin, Kerry, Belfast, Waterford and Galway. This section alone is a pure treasure for the family researcher.