The calculated distance (air line) between Kosan and Chaeryŏng-ŭp is approximately 102 miles respectively 165 kilometers.
By car or train, the actual journey to Chaeryŏng-ŭp is certainly longer, as only the direct route (as the crow flies) between Kosan and Chaeryŏng-ŭp has been calculated here.
Air line (approximately)
165 kilometers
89 nautical miles