The National Archives of Ireland in partnership with Library and Archives Canada has digitised the household returns and ancillary records for the censuses of Ireland in 1901 and 1911, and you can search them and view the results for free.
The 1901 census is arranged by street or in rural areas, by townland (the smallest division of land).
Just like our censuses, it shows each member of the household; name, age, gender, relationship to head of the household, religion, occupation, marital status and county or country of birth, and whether they can speak Gaelic (although in this case it's presumably Irish Gaelic). In 1901, there were fewer differences between Irish Gaelic and Scottish Gaelic, and my granny who was a native speaker of Scottish Gaelic rarely had any difficulty in reading Irish Gaelic or talking to people who spoke Irish Gaelic, and generally they understood her.
The 1911 census also shows for wives: the number of years married, the number of children born and the number still alive.
Thanks to Marjorie Gavin for drawing my attention to this resource.