More than a fifth of all Irish passports issued in the last year went to people living in the UK - a surge which has been directly linked to Brexit.
The Department of Foreign Affairs said a record number of passports - more than 779,000 - were issued in 2017.
A total of 81,752 Irish citizens in Northern Ireland sought Irish passports, an increase of almost 20% on the previous year.
In Britain demand for the documents soared by more than 28% to 81,287.
The Department of Foreign Affairs said it received 785,026 passport applications during 2017 but it only issued 779,184.
Tánaiste and Minister for Foreign Affairs Simon Coveney said: "This is the highest number of Irish passports ever issued in one year.
"It represents an increase of over 6% compared to 2016 (itself a record-breaking year), and an increase of over 15% since 2015.
"The number of applicants from Northern Ireland and Great Britain has continued to rise.
"Overall, almost 20% of the total number of applications received by the passport service this year were from Irish citizens in Northern Ireland or Great Britain."
Prior to the post-Brexit surge in interest in Irish passports about 50,000 Irish passports were usually issued in Britain each year.