The calculated distance (air line) between Sendai and Minami-Sōma is approximately 44 miles respectively 72 kilometers.
By car or train, the actual journey to Minami-Sōma is certainly longer, as only the direct route (as the crow flies) between Sendai and Minami-Sōma has been calculated here.
Air line (approximately)
72 kilometers
39 nautical miles