The calculated distance (air line) between Yŏnan-ŭp and Yangp'yŏng is approximately 78 miles respectively 126 kilometers.
By car or train, the actual journey to Yangp'yŏng is certainly longer, as only the direct route (as the crow flies) between Yŏnan-ŭp and Yangp'yŏng has been calculated here.
Air line (approximately)
126 kilometers
68 nautical miles