Answer:
Head south towards the city of Dublin from the airport. Join the M50 motorway at junction 1. At junction 9, take the R110/N7 exit to City Centre. Keep right at the fork, following signs for Cluain Dolcaín/Clondalkin. At the Red Cow Roundabout, take the 3rd exit onto N7/Naas Rd heading to Luimneach/Limerick. Follow the N7, which later becomes the M7. At junction 11, exit onto M9 toward Waterford/Kilkenny/Carlow. Continue onto the N9 following the signs. The N9 will take you to Carlow. The journey is about 60 miles or 100 kilometres.