The calculated distance (air line) between Hongwŏn and Chaeryŏng-ŭp is approximately 168 miles respectively 271 kilometers.
By car or train, the actual journey to Chaeryŏng-ŭp is certainly longer, as only the direct route (as the crow flies) between Hongwŏn and Chaeryŏng-ŭp has been calculated here.
Air line (approximately)
271 kilometers
146 nautical miles