The calculated distance (air line) between Nenagh Bridge and Dún Laoghaire is approximately 90 miles respectively 145 kilometers.
By car or train, the actual journey to Dún Laoghaire is certainly longer, as only the direct route (as the crow flies) between Nenagh Bridge and Dún Laoghaire has been calculated here.
Air line (approximately)
145 kilometers
78 nautical miles