The calculated distance (air line) between Ch’ŏngdan-ŭp and Kangsŏn is approximately 69 miles respectively 112 kilometers.
By car or train, the actual journey to Kangsŏn is certainly longer, as only the direct route (as the crow flies) between Ch’ŏngdan-ŭp and Kangsŏn has been calculated here.
Air line (approximately)
112 kilometers
60 nautical miles