The calculated distance (air line) between Sŭngho 1-tong and Kanggye is approximately 140 miles respectively 226 kilometers.
By car or train, the actual journey to Kanggye is certainly longer, as only the direct route (as the crow flies) between Sŭngho 1-tong and Kanggye has been calculated here.
Air line (approximately)
226 kilometers
122 nautical miles