Figures published by the Department of the Environment show that between mid-February and 5 May, over 65,911 people secured the right to vote in Friday's referendums by getting onto the supplementary electoral register.
The Yes Equality campaign has hailed what it termed the 'phenomenal' figure saying it equates to approximately 2,000 new voters joining the register every day.
In a statement, it says the surge of new voters comes on foot of a concerted 'register to vote' effort by Yes Equality and other campaigners to ensure that the voices of as many citizens as possible are heard in the marriage referendum.
The group says today's figures follow the addition of 40,000 new voters to the electoral register following a youth and student-focussed voter registration drive in November last year.
Among today's other figures are:
Cork City 2,545
Waterford City & County 1,914
Limerick City & County 1,787
Galway County 1,706
Galway City 1,393