The calculated distance (air line) between Hyesan-dong and Hongwŏn is approximately 95 miles respectively 154 kilometers.
By car or train, the actual journey to Hongwŏn is certainly longer, as only the direct route (as the crow flies) between Hyesan-dong and Hongwŏn has been calculated here.
Air line (approximately)
154 kilometers
83 nautical miles