The calculated distance (air line) between Changam-ch’on and Ŭndŏk is approximately 155 miles respectively 249 kilometers.
By car or train, the actual journey to Ŭndŏk is certainly longer, as only the direct route (as the crow flies) between Changam-ch’on and Ŭndŏk has been calculated here.
Air line (approximately)
249 kilometers
134 nautical miles