The calculated distance (air line) between Apatin and Sremska Mitrovica is approximately 57 miles respectively 92 kilometers.
By car or train, the actual journey to Sremska Mitrovica is certainly longer, as only the direct route (as the crow flies) between Apatin and Sremska Mitrovica has been calculated here.
Air line (approximately)
92 kilometers
50 nautical miles