The calculated distance (air line) between Sinegorskiy and Rostov-na-Donu is approximately 75 miles respectively 121 kilometers.
By car or train, the actual journey to Rostov-na-Donu is certainly longer, as only the direct route (as the crow flies) between Sinegorskiy and Rostov-na-Donu has been calculated here.
Air line (approximately)
121 kilometers
65 nautical miles