The calculated distance (air line) between T’ongch’ŏn-ŭp and Kanggye is approximately 156 miles respectively 250 kilometers.
By car or train, the actual journey to Kanggye is certainly longer, as only the direct route (as the crow flies) between T’ongch’ŏn-ŭp and Kanggye has been calculated here.
Air line (approximately)
250 kilometers
135 nautical miles