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