The calculated distance (air line) between Kangdong-ŭp and Sinŭiju is approximately 112 miles respectively 180 kilometers.
By car or train, the actual journey to Sinŭiju is certainly longer, as only the direct route (as the crow flies) between Kangdong-ŭp and Sinŭiju has been calculated here.
Air line (approximately)
180 kilometers
97 nautical miles