IT IS 170 years since the first one was carried out, with the current edition involving a print run of two million forms and a cost of €57m over the four-year process of planning and sifting through the results.
Census 2011 has arrived and, by the end of March, the 1.8 million households throughout the country will have received a census form to complete.
Up to 10,000 crates packed with census forms will leave a warehouse in Co Dublin this week as the task of delivering them ahead of census night on Sunday, April 10 begins.
The process of developing the current census form began in 2009, when the CSO conducted a test involving 8,000 households across the country.
This year's census operation will involve 50 full-time senior workers, 440 full-time field supervisors who will work from their own homes, and 5,000 part-time enumerators who will deliver and collect the census forms from homes over the 10 weeks of the "field" campaign.
On March 11, census enumerators will begin calling to homes delivering forms and these will then be collected after census night on April 10.
Preliminary results will be available three months after the census, with principal demographic data out within a year.