The calculated distance (air line) between Trieste and Gradisca d'Isonzo is approximately 21 miles respectively 34 kilometers.
By car or train, the actual journey to Gradisca d'Isonzo is certainly longer, as only the direct route (as the crow flies) between Trieste and Gradisca d'Isonzo has been calculated here.
Air line (approximately)
34 kilometers
19 nautical miles