The calculated distance (air line) between Yonggang-ŭp and Hongwŏn is approximately 157 miles respectively 253 kilometers.
By car or train, the actual journey to Hongwŏn is certainly longer, as only the direct route (as the crow flies) between Yonggang-ŭp and Hongwŏn has been calculated here.
Air line (approximately)
253 kilometers
137 nautical miles