The National Archives of Ireland has recently made the Census of 1901 searchable online. The 1901 and 1911 censuses cover the 32 counties of the island of Ireland and are the only surviving full censuses that are open to the public. They are searchable by all information categories and give access to over 4 million records
The 1901 census was taken on 31st March 1901. The 1911 census was taken on 2 April 1911. The census contains basic topographical divisions: : County; District Electoral Division; Townland or Street. The 1901 census lists, for every member of each household; relationship to head of the household name, age, sex, religion, occupation, marital status, county or country of birth, whether they could read of write and whether they spoke the Irish language.
The website was launched in december 2009 and the 1911 census has been available since August 2009. The images and databases are enhanced by historical commentary and photographs from early 20th century Ireland, what various counties were like during this time, their religion, history, education, transport, poverty and health, sport, emigration, social life, sport, literary life, government and politics, and law and order.
Visit and search the Censuses online at http://www.census.nationalarchives.ie/