Almost three-quarters of couples who got married in Co Mayo last year had Catholic marriage ceremonies.
New figures from the CSO show that, nationally, nearly one-third of opposite-sex couples opted for a civil marriage in 2019.
However in Mayo, of the 682 opposite-sex marriages last year, 504 had a Catholic ceremony while 94 had a civil marriage ceremony.
There were 10 same-sex marriages in Mayo last year, of which 6 were civil ceremonies.
The national figures published show the average age of grooms is the highest to date at 36.8 years while the average bride's age was 34.8.
Those in same-sex marriages tend to be older when they tie the knot.
Friday and Saturday continue to be the most popular days of the week for weddings, and August was the most popular month.