Irish Road Race Circuits https://goo.gl/maps/e51dQAsSqfnFriAq7
I guess the best known are:
Cookstown 100
https://www.cookstown100.org/
Tandragee 100
https://www.tandragee100.co.uk/
North West 200
https://www.northwest200.org/
Southern 100
https://southern100.com/
Armoy Road Races
https://amrrc.com/
Ulster Grand Prix
https://ulstergrandprix.net/
And, by cheating a bit, the Isle of Man TT in June and Isle of Man Classic TT later in the year
https://www.iomtt.com/
I guess the best known are:
Cookstown 100
https://www.cookstown100.org/
Tandragee 100
https://www.tandragee100.co.uk/
North West 200
https://www.northwest200.org/
Southern 100
https://southern100.com/
Armoy Road Races
https://amrrc.com/
Ulster Grand Prix
https://ulstergrandprix.net/
And, by cheating a bit, the Isle of Man TT in June and Isle of Man Classic TT later in the year
https://www.iomtt.com/