According to the latest release by the CSO from last year's Census, Catholicism remains the predominant religion, accounting for 87 per cent (113,481 ) of Mayo’s population. However, this was down from 117,721 persons five years previously. The average age of Catholics in the county was 40.6 years, slightly above the county’s overall average age of 40.2 years.
As with the State overall, the next largest group was those with no religion. In 2011, the 4,994 people with no religion comprised 3.8 per cent of the county’s population. By 2016, this had increased to 7,604 people comprising 5.8 per cent of the county’s population. Their average age was 37 years, making them 3.2 years younger on average than the county’s population overall.
The 2,631 Church of Ireland members in the county made up two of its total population. On average, Church of Ireland members in Mayo were 4.5 years older (44.7 years ) than the overall population in the county. Muslims (1,265 ) and Orthodox (633 ) completed the top five.