The calculated distance (air line) between Sŭngam-nodongjagu and Hyesan is approximately 79 miles respectively 128 kilometers.
By car or train, the actual journey to Hyesan is certainly longer, as only the direct route (as the crow flies) between Sŭngam-nodongjagu and Hyesan has been calculated here.
Air line (approximately)
128 kilometers
69 nautical miles