The calculated distance (air line) between Elefthério - Kordelió and Sérres is approximately 45 miles respectively 72 kilometers.
By car or train, the actual journey to Sérres is certainly longer, as only the direct route (as the crow flies) between Elefthério - Kordelió and Sérres has been calculated here.
Air line (approximately)
72 kilometers
39 nautical miles