The calculated distance (air line) between Hyesan-dong and Hoeryŏng is approximately 108 miles respectively 174 kilometers.
By car or train, the actual journey to Hoeryŏng is certainly longer, as only the direct route (as the crow flies) between Hyesan-dong and Hoeryŏng has been calculated here.
Air line (approximately)
174 kilometers
94 nautical miles