The calculated distance (air line) between Sŭngam-nodongjagu and Hongwŏn is approximately 145 miles respectively 233 kilometers.
By car or train, the actual journey to Hongwŏn is certainly longer, as only the direct route (as the crow flies) between Sŭngam-nodongjagu and Hongwŏn has been calculated here.
Air line (approximately)
233 kilometers
126 nautical miles