The proportion of the population who reported themselves to be Roman Catholic fell by 4 per cent to 69 per cent between 2016 and last year, according to the latest census results.
The number with no religion increased by 62 per cent to nearly three-quarters of a million (736,210), which represented some 14 per cent of the population.
The Church of Ireland category showed little change but remained the second largest religious category with 124,749 people (2 per cent). Other categories with large numbers included Orthodox (100,165) and Islam (81,930). The number of Hindus more than doubled from 13,729 to 33,043.
A regional breakdown of the results shows that smaller and more rural counties tended to have the highest proportion of people who identified as Catholic, with urban areas having the lowest. For example, Mayo had the highest proportion of Catholics (80 per cent), followed by Tipperary, Offaly, Roscommon and Galway (all 79 per cent).
By contrast, the Dublin City Council area recorded the lowest percentage of Catholics (53 per cent).
Counties or local authority areas with the highest proportion of people with no religion were Dún Laoghaire-Rathdown (24 per cent); Dublin City Council (23 per cent); Wicklow (20 per cent); Cork City Council (18 per cent); and Fingal (17 per cent). Monaghan had the lowest proportion with no religion, at just 7 per cent.
When religion was measured by citizenship, there were significant differences between Irish and non-Irish citizens.
Irish citizens accounted for almost 94 per cent of Roman Catholics, but only 25 per cent of people in the Hindu category, for example.
Census officials cautioned that the question on religion used in last year’s census differed from previous census in 2016, which may impact on comparability.
While the 2016 census asked “what is your religion?’’, the 2022 census asked “what is your religion, if any?”. Response categories also changed in last year’s question, with “no religion” listed as the first response option.