The calculated distance (air line) between Athy and Dún Laoghaire is approximately 41 miles respectively 66 kilometers.
By car or train, the actual journey to Dún Laoghaire is certainly longer, as only the direct route (as the crow flies) between Athy and Dún Laoghaire has been calculated here.
Air line (approximately)
66 kilometers
35 nautical miles