The calculated distance (air line) between Hyesan-dong and Hepingjie is approximately 80 miles respectively 129 kilometers.
By car or train, the actual journey to Hepingjie is certainly longer, as only the direct route (as the crow flies) between Hyesan-dong and Hepingjie has been calculated here.
Air line (approximately)
129 kilometers
70 nautical miles