The calculated distance (air line) between Yonggang-ŭp and Hŭngnam is approximately 136 miles respectively 219 kilometers.
By car or train, the actual journey to Hŭngnam is certainly longer, as only the direct route (as the crow flies) between Yonggang-ŭp and Hŭngnam has been calculated here.
Air line (approximately)
219 kilometers
118 nautical miles