The calculated distance (air line) between Acilia-Castel Fusano-Ostia Antica and Terni is approximately 58 miles respectively 93 kilometers.
By car or train, the actual journey to Terni is certainly longer, as only the direct route (as the crow flies) between Acilia-Castel Fusano-Ostia Antica and Terni has been calculated here.
Air line (approximately)
93 kilometers
50 nautical miles