The calculated distance (air line) between Smederevo and Sremska Mitrovica is approximately 68 miles respectively 109 kilometers.
By car or train, the actual journey to Sremska Mitrovica is certainly longer, as only the direct route (as the crow flies) between Smederevo and Sremska Mitrovica has been calculated here.
Air line (approximately)
109 kilometers
59 nautical miles