The calculated distance (air line) between Kraljevo and Sremska Mitrovica is approximately 101 miles respectively 163 kilometers.
By car or train, the actual journey to Sremska Mitrovica is certainly longer, as only the direct route (as the crow flies) between Kraljevo and Sremska Mitrovica has been calculated here.
Air line (approximately)
163 kilometers
88 nautical miles