The 1966 Census of Ireland was held on 17 April 1966. It was organised by the Central Statistics Office (CSO) and reported a total population of 2,884,002, which was a 2.3% increase in a span of five years. The total population rebounded from a record low of 2,818,341 recorded in the 1961 census, although northern and western regions continued to steeply decline in population. The census results were released gradually across seven volumes between 1967 and 1970.
For each household surveyed, the 1966 census requested the number of rooms in the dwelling occupied by the household, as well as ten primary pieces of information on each individual present, which were:
The seven volumes and their release schedule are as follows:
The total population of the Republic of Ireland according to the 1966 census was 2,884,002 of whom 1,449,032 (50.24%) were male and 1,434,970 (49.76%) were female. The population breakdown by province and county, and by city, are outlined below. While the total national population increased by 2.3% since the 1961 census, there were large regional variations, with northern and western counties in particular continuing a steady trend of depopulation. County Dublin experienced rapid growth of over 10% during this period, while every county in Connacht and Ulster<small></small> recorded a population decrease.
The census returns of 1966 are confidential until 2066 due to Section 35, of the 1993 Statistics Act which bans the release of census return forms until 100 years after the enumeration date. However, the reports published by the Central Statistics Office and are available online from the CSO website to freely access.