The calculated distance (air line) between Sŭngam-nodongjagu and Hŭngnam is approximately 165 miles respectively 266 kilometers.
By car or train, the actual journey to Hŭngnam is certainly longer, as only the direct route (as the crow flies) between Sŭngam-nodongjagu and Hŭngnam has been calculated here.
Air line (approximately)
266 kilometers
144 nautical miles